Praise be to Allah.
The Islamic texts forbid all sins and close the doors that lead to them; they forbid cooperating in sin and transgression, and imitating the sinners; and they explain that the one who loves a people will be gathered with them (on the Day of Resurrection) and the one who imitates a people is one of them.
Among the things that Islam forbids is watching those movies, soap operas and music shows, and any kind of entertainment that includes any kind of sin.
Watching such things implies approval of what the people in them are doing and of the falsehood they are indulging in. Anyone who sees an evil and approves of it and accepts it, and does not denounce it, comes under the same rulings as the one who does it.
Allah, may He be exalted, says (interpretation of the meaning):
“And it has already been revealed to you in the Book (this Quran) that when you hear the Verses of Allah being denied and mocked at, then sit not with them, until they engage in a talk other than that; (but if you stayed with them) certainly in that case you would be like them”
Ibn Katheer (may Allah have mercy on him) said:
That is, if you sit with them and approve of what they are doing, then you are equal to them in the sin they are committing. End quote.
Tafseer Ibn Katheer, 3/278
As-Sa‘di (may Allah have mercy on him) said:
That is, if you sit with them in the situation mentioned then you are like them, because you have approved of their disbelief and mockery, and the one who approves of sin is like the one who does it. The point is that the one who attends a gathering in which Allah is disobeyed has an individual obligation to denounce them, if he is able to do so, or to get up and leave, if he not able to denounce it. End quote.
Tafseer as-Sa‘di, p. 210
Shaykh al-Islam [Ibn Taymiyah] (may Allah have mercy on him) said:
It is not permissible for anyone to willingly attend gatherings of evil when there is no need to do so, as it says in the hadeeth: “Whoever believes in Allah and the Last Day, let him not sit at a table at which alcohol is drunk.” Some people who had been drinking alcohol were brought to ‘Umar ibn ‘Abd al-‘Azeez and he ordered that they be flogged. It was said to him: Among them is one who is fasting. He said: Start with him; have you not heard that Allah says (interpretation of the meaning): “And it has already been revealed to you in the Book (this Quran) that when you hear the Verses of Allah being denied and mocked at, then sit not with them, until they engage in a talk other than that; (but if you stayed with them) certainly in that case you would be like them” [an-Nisa’ 4:140]?
‘Umar ibn ‘Abd al-‘Azeez (may Allah be pleased with him) explained that Allah regards the one who is present when evil is being committed as being like the one who does it. Hence the scholars said: If he is invited to a feast in which evils are present, such as alcohol and musical instruments, it is not permissible to attend it. That is because Allah, may He be exalted, has commanded us to denounce evil as much as possible. So if a person attends willingly and does not denounce it, he has disobeyed Allah and His Messenger by failing to do what He has commanded him of denouncing and forbidding evil. As that is the case, if a person willingly attends gatherings where alcohol is served when there is no need to do so, and he does not denounce evil as Allah has enjoined, then he is a partner with the evildoers in the evildoing and he is regarded as one of them. End quote.
Majmoo‘ al-Fataawa, 28/221-222
Muslim (1854) narrated from Umm Salamah, the wife of the Prophet (blessings and peace of Allah be upon him), that the Prophet (blessings and peace of Allah be upon him) said: “There will be appointed over you rulers (whose good deeds) you approve of and (whose bad deeds) you object to. Whoever dislikes (their bad deeds) will be free of blame and whoever objects (to them) will also be safe, but whoever approves and follows (is blameworthy).”
So whoever sits and listens to such evil or watches it is a partner in sin with those who do it. If it involves kufr – Allah forbid – such as reviling Islam or casting aspersions upon the messages or the Messengers, or belittling the rulings and laws of Islam, or mocking them, such as the beard and niqab – as many misguided people do nowadays – and he sits and listens to them and does not get angry for the sake of Allah, and he is pleased with what they are saying, then he is like them.
Allah, may He be exalted, says (interpretation of the meaning):
“If you ask them (about this), they declare: ‘We were only talking idly and joking.’ Say: ‘Was it at Allah and His Ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) and His Messenger (SAW) that you were mocking?’
Make no excuse; you have disbelieved after you had believed”
[at-Tawbah 9:65, 66].
Whoever utters a word of kufr, or does an action that implies kufr, knowing that it is kufr, is a kaafir, whether he does it in earnest or in jest. And whoever listens to it and does not denounce it, and approves of what is said or done, is a kaafir like him. In fact, if he does not approve of that evil and hate it in his heart, but he did not get up and leave when he was able to do so, he is sinning just by sitting there. Even if he was safe from kufr, he was not free of sin; he was not safe from falling into the sin of sitting in that place.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) was asked:
I am a religiously-committed young man. During these blessed nights [of Ramadan] I sit with some young people to relax, but sometimes someone may come along who smokes cigarettes or shisha. What should I do in that case?
He replied: The Prophet (blessings and peace of Allah be upon him) said: “Whoever among you sees an evil action, then let him change it with his hand [by taking action]; if he cannot, then with his tongue [by speaking out]; and if he cannot, then with his heart…” So if someone comes to your gathering and smokes a cigarette, advise him first, and if he stops that is good for you and for him. But if he does not stop and you are able to kick him out of the place, then kick him out, because you are able to change the evil with your hand (by taking action). But if you are not able to do that, because the place is not yours, then you should leave, because you are not able to change it with your words or with your actions, so what is left? The heart cannot denounce something and stay with the one who is doing it, so you should leave. Some people say that they sit with them whilst hating it in their hearts. But we say: Subhaan Allah! This is a contradiction. If you hate it in your heart, then who is forcing you to stay? There is no compulsion. Anyone who denounces something in his heart has no choice but to leave the place. If he claims that he hates it in his heart but he still stays in that place, then he is lying.
Al-Liqa’ ash-Shahri, 3/45
For more information please see the answer to question no. 1107
To sum up:
If a person watches or listens to that and approves of it, then he comes under the same rulings as the one who does it. If he hates it in his heart but he continues to watch and listen, then he is in grave danger; if he is free from kufr he will not be safe from falling into sin and disobedience.
And Allah knows best.