I don't remember who said it, but someone on this forum gave a really good advice on how to deal with bullying.
Basically bullies want to show superiority over you. They can do that in many ways, such as scaring you into doing things for them, make fun of things you're ashamed of, or, in this particular case, taunt you to make you retaliate, so they can twist the story around to make you into the bad guy, but it's always to show dominance. Also creating drama is an easy way to get views on youtube.
Basically you have to show the bully that his tactics is not making you feel inferior. Implying that their actions actually makes them inferior is the cherry on the cake. For example if a bully threatens to hit you, you can say something like "yeah, I could tell you're the type of person who gets their way with violence... I guess that's all you can do uh?" in a disgusted tone. Another option would be to laugh it off as if what they said was silly.
In some cases, ignoring won't work because it can be considered a submissive behavior. It can be a good strategy in some cases, but if it doesn't work something else has to be done, the right thing to do depends on what the bully wants though. Retaliation is not often the right answer.
Also if you go debate with him he can try to drive the conversation towards what he wants, so I wouldn't recommend taking on his offer unless you know all the tactics he might use and how to deflect them. Also it would have to be live so he can't edit your words.
A response video would be easier but it would give him views, so I would only recommend it if he had a bigger channel (so you would be the one getting views thanks to him!)
Honestly I don't see the point of arguing with him since he has only 3 subs. If you want to let people know that furries are not as bad as people think I would suggest making/sharing content doing just that, instead of giving him attention by addressing him directly (or even mentionning his name).
Society is already starting to see furries a lot less negatively than it used to though, so I don't see this guy as a threat.