Annoying, for sure. But, an emerging indicator of an attention economy platform starting to mature a little bit. I'm not much of a youtuber, but my kids are and I am constantly in awe of the spammy comment threads on popular videos there. And the "subscribe to me!" spam maybe gets those people fractions of cents per clicks, so converting is not as big of a deal as it is here.
Must mean you are doing something right @rok-sivante if the spammers are flocking your way!