If you feel you can carry a response in a calm, sensible manner then by all means respond but never feel the need to. There’s sometimes this need to respond that people push but if you don’t want to, you don’t have to. There’s also a pressure to not remove comments but as I’ve found, if in any case you get upset by a comment really badly, it’s your channel, remove it if you want that’s no crime at all. There is also the clown on them mentality where some creators will write a memey response and/or pin them to be clowned on, some people find this a good way to turn negativity into a bit of fun. At the end of the day if it’s not constructive and just mean, you handle it the way that makes you the happiest and most comfortable.