Done that. I've reported users, block users, hid users. It does no good because they always use a different user account to post their spam on my videos. This is a concerted effort by a website to spam videos. I know I am not the only one. If they are doing it to me, they are doing it other users. They only spam my carpentry How To videos. Surely youtube has a way to allow us to report that website that is intentionally spamming user videos. This has been going on for months now.
These user accounts that are doing the spamming (possibly robots) are doing it for this WoodPrix website trying to get people to go to their website and by their products. There had to be a way to warn this website owner that if they do not stop spamming youtube user videos, they will face legal action, or something like that.