It would bother me a little bit less if it wasn't so incredibly obvious. I have a couple of commenters who literally post the same comment on every single video I post, and it's meaningless and annoying. After a time, though, it can be fun to see if you can get them to engage. Sometimes, I'll ask really complex questions after people say, "Great video! Check out my channel," I'll say, "What did you like about the video? I'm so glad you appreciated it, what part resonated with you?" It's kind of passive-aggressive, but sometimes it cuts through the anger.