The fact that I cant go to YT and select play all on a channel anymore makes its primary use, music, pointless to me.

This, my humorous fellow netizen, means:

Something AND something make the primary use (of said thing, YouTube), music (the specification of what is the primary use), pointless to me (such that I did not find said primary use any longer possible).

We know what you mean because we are charitable enought not to assume you think the primary use of youtube is music, but you fucked the wording up and I made fun of you for that.

What you wanted to say should have been phrased as it follows:

The fact that I cant go to YT and select play all on a channel anymore makes my primary use, listening to music, impossible.

Now if public school in your country were better funded, you'd understand that my poking fun of you also had a different implication: it's not that unreasonable for YouTube to stop people from sucking huge bandwith to stream videos just for the minimal amount of sound data attached.