Is watching haram video on YouTube help in sin? Because by watching it the video will get more view, and if the video get many view it will get reccomended by youtube to other people or it will placed at top trending because that , are this considered help in sin because indirectly promote the haram video although Im not intended to promote it? And am I being responsible for new other sin who watch it because that?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is impermissible to watch YouTube videos that contain prohibitions - such as those that promote corrupt ideas, feature a picture of an unveiled woman, music, etc.

Watching these videos on these websites involves promoting them and helping others watch them. Therefore, it is feared that whoever watches these prohibited videos would bear sin for it. A sinner bears sin for causing others to commit sins even if he did not intend to help them to do so. Allah, The Exalted, Says (what means): {That they may bear their own burdens in full on the Day of Resurrection and some of the burdens of those whom they misguide without knowledge. Unquestionably, evil is that which they bear.} [Quran 16:25]

A person would be rewarded or punished for the consequence of his acts of obedience or disobedience. Allah, The Almighty, Says (what means): {Indeed, it is We who bring the dead to life and record what they have put forth and what they left behind (consequences), and all things We have enumerated in a clear register.} [Quran 36:12]

The Prophet said: “Whoever introduces a good practice in Islam, will get a reward for it and a reward for all those who act upon it until the Day of Judgment without anything being diminished from their rewards. And whoever introduces an evil practice in Islam will shoulder its sin and the sins of all those who will act upon it, without diminishing in any way their burden.” [Muslim]

He also said: “No person who is killed unjustly, but the share of (this offense of his also) falls upon the first son of Adam because he was the first person to commit the act of killing.”

Ibn Taymiyyah said in Jami’ Al-Massa’il: “If it is said that it is authentically reported that the Prophet said: “No person who is killed unjustly, but the share of (this offense of his also) falls upon the first son of Adam because he was the first person to commit the act of killing,” [Al-Bukhari and Muslim] and Adam’s son did not intend to prompt all the killers to commit that sin.

In refutation, the Hadeeth did not specify that he would bear equal sins of all murderers. He, sallallahu ‘alayhi wa sallam, rather stated that Adam’s son bears a share of the sin of the murderer because he was the first person to introduce the tradition of killing. Allah, The Exalted, Says about the leaders of disbelief (what means): {And those who disbelieve say to those who believe, "Follow our way, and we will carry your sins." But they will not carry anything of their sins. Indeed, they are liars. But they will surely carry their [own] burdens and [other] burdens along with their burdens, and they will surely be questioned on the Day of Resurrection about what they used to invent.} [Quran 29:12-13] Allah also Says (what means): {That they may bear their own burdens in full on the Day of Resurrection and some of the burdens of those whom they misguide without knowledge.} [Quran 16:25]

A person may be rewarded or punished for the consequences of his deeds even if they were unintentional. Having equal rewards earned by a doer of a good deed is a partial juridical case that falls under this category.”

However, when a person watches a prohibited video on this website, this does not entail that he is the only reason that all other people would watch it afterward. Accordingly, it is not accurate to say that the viewer of these videos bears the sin of everyone who watches them after him.
Rather, it may be said that the viewer contributed to promoting the video, and bears sin for that, in addition to the sin of watching the prohibited video.

An important point should be highlighted in this regard. The warnings (reported in the Sharee‘ah texts regarding certain sins) do not necessitate that the doer of such sins would inevitably be subjected to the promised punishment. There may be impediments such as sincere repentance and performing good deeds that wipe out misdeeds, and many others.

Allah knows best.