Perhaps on review of specific ad presentation practices, you could argue for a degradation of experience, but showing adds more or less within YouTube to free users seems like an acceptable method of generating revenue.
As an aside, the fact that people pay for cable and still have 4-7 minute ad-breaks every 15 minutes make anything YouTube does pale in comparison.
Except for the tracking that ads use and the possibility of getting malware because they aren't curated as well as they should be.
I also don't like companies aggressively trying to get me to buy stuff I don't want. Show a static image on the right somewhere with a link. Hell, show a dozen of them. Still less intrusive than an ad that shows up while you're in the middle of a video.
But the poor ad companies are apparently on the brink of bankruptcy based on how hard they are pushing things. Just a little bit of composure or any respect for the people that they are pushing these on and I'd have a different viewpoint. But they are always all-in on this.
As an aside, the fact that people pay for cable and still have 4-7 minute ad-breaks every 15 minutes make anything YouTube does pale in comparison.