The Prophet’s Sunnah is the second source of Islamic sharee‘ah. The revelation came down to the Prophet (blessings and peace of Allah be upon him) with the Sunnah as it came down to him with the Qur’an. Allah, may He be exalted, has enjoined upon the believers complete submission to the words of the Prophet (blessings and peace of Allah be upon him) and his hadith and rulings, to the extent that He, may He be glorified, swore by His divine self that whoever hears the words of the Prophet (blessings and peace of Allah be upon him), then rejects them and does not accept them, has nothing to do with faith at all. Hence there was consensus among the scholars that whoever denies that the Sunnah constitutes shar‘i evidence in general terms, or rejects a hadith of the Prophet (blessings and peace of Allah be upon him – knowing that it is the words of the Prophet (blessings and peace of Allah be upon him) – is a disbeliever, who has not attained even the lowest level of Islam and submission to Allah and His Messenger.
As Muslims we abide by the Quran and the Sunnah of the prophet PBUH. The Sunnah of the prophet PBUH is extrapolated from the ahadeeth, for example the Quran tells us to pray, but doesn't tell us details such as, "pray 5 times a day at this time, for fajr only pray 2 rakah, for duhr pray 4, sit in 2nd rakah etc..."
The science of hadith is extraordinary, it uses a chain of narrators, which allows us to see if its a sahih (authentic) hadith by the prophet PBUH or fabricated, the same cannot be said for other religions. Allah in the Quran tells us to obey him and obey the prophet, and we obey the prophet from his sunnah which again is extrapolated from hadith.
What I see is that Muslims generally don't know what is precisely legal and illegal. There are some Muslims who says that watching films is completely illegal, but there is an opinion that it is legal if it will not disrupt daily duties.
Muslims when it comes to the pillars of Islam and Quran know whats halal and haram. For example, Allah in Quran tells us not to eat pork, so almost every Muslim knows that its haram to eat pork their is no confusion here.
But then their are what Muslims call "minor sins" when it comes to things such as movies, music, beard, cursing etc... Some of these minor sins are not mentioned in Quran directly but are mentioned in hadith. Some know that these are sins regardless of major or minor while others do not know due to lack of knowledge. For example, I always saw my family listen to music so I thought it was okay, but when I gained knowledge on the topic I learned it was haram.
Yes their are topics that Muslims are not sure if they are haram or halal and they disagree over them, but we are commanded to refer to Quran and Sunnah when this happens. For example the issue of growing a beard. Some Muslims are of the view that its optional, this is their default answer basically, but they don't bother to spend some time referring to all instances where the beard is mentioned in hadith or learning what the majority or consensus of scholars say on the topic. Some Muslims like to go with a minority view or do what we call "fatwa shopping" to satisfy whims and desires. At the end of the day, Allah knows our intentions and he will deal with each and every one of us based off our actions and intentions.
Learning from the scholars as well is what solves a lot of confusion and Allah knows best.
In regards to watching film, if the Muslim who is confused does a little research on the topic he will come to know that as long as the movie doesn't have nudity, music, anti-religious messages then its okay to watch it as along as he does his obligations to Allah.
There are several other dilemma and discussions about halal/haram classification. Who is right then, I don't know. If you were right, well, all things I do today would be, in your opinion, "haram", also not permitted.
Yes as a layman their is definitely confusion when it comes to "minor sins", thats why the solution here is to refer back to Quran, Sunnah, and the scholars and in shaa Allah that dilemma is solved.
Thats the method I personally prefer at least, I refer to Quran, Hadith and look at the majority view of the scholars and the four schools of thought and take the majority position, not the minority position.
For example I know many layman that are Hanafi or Shafi or other schools of thought and they just follow their school and that way they are not put in situations where they say "is this haram or halal" but can refer to their school of thought and see what they say on the topic.