My concern is that do such comments get deleted because some people report them ?
Or they are directly seen by the mods and they delete them ?
Both of those things happen. If you report a post, it will go on the
to do list of the responsible staff member who then has to take action. Depending on what it it is, the post can get deleted, merged with a previous one, or left the way it is if the mod is unsure.
Welsh said himself that he doesn't just sit around and wait for other members to report something. He browses the sections he is responsible for and deleted whatever he feels breaks the rules:
Also, regarding it potentially not being reported. Usually, I tend to go through some of the sections I moderate, and delete replies which haven't been reported, but I believe to be breaking the guidelines. That's just something I do, and I'm sure other moderators here do it too. Same as if we just happen upon your response, like any other user instead of reporting it, we would just remove it if we believe it infringes the guidelines.
So, posts can be deleted whether or not they've actually been reported, but this doesn't mean we are targeting you.