No such thing as bad publicity my friend. I've honestly never seen a video with more dislikes than likes, so it's good to know that 99% of dislikers are either trolls or just doing it to wind you up, whereas 100% of people who 'like' a video do so because... well, they actually like it!
You've never seen a video with more dislikes than likes? May I offer exhibit A) My video "Tutorial, how to switch to uploads only" That video was hit by a tsunami of hate hahahahahahaha And let's not kid ourselves here, some people make horrible content. It may be just terribly awkward, it may be like they put no thought into at all, and good normal people might dislike that video. They might even come in the comments and be like "what was the point of this" or "I think you should try something different this isn't your thing" And they literally mean what they're saying. They think you're embarrassing yourself and they are telling you.
However, the way to know whether or not it's that, or just "trolls", is by the way they comment, and by the ratio. If you are getting almost no likes, all dislikes, and the comments aren't JUST cruel, they're people saying things like "Yeeeeah... I see what you were trying to do and it was a nice try but just... no man.. no" Things like that? You may need to rethink your content.
But if you're getting good mixed with bad and the ratio is more likes than dislikes, then don't worry about the haters, they're just not your market. And lastly, if a video suddenly jumps in views and then tons and tons of nasty people flood in out of nowhere saying nothing productive but just "kill yourself!!!" and stuff? Don't fret. You've been put on 4 chan or the cringe section of reddit or some place where trolls gather just to hate on people.
So keep these things in mind. Hate doesn't ALWAYS mean there's trolls on the other end of this, you gotta look at the evidence and decide if it's you or them.