Questions with no or no upvoted answers (as the one referenced in the question) will get reinfected into the front page a few times automatically to get more attention. As no user is involved the user is shown as "community".
Like many users, community has a profile page that explains what they like to do on the site. In this case, community is a robot ...
In general comments are considered to be temporary information which can (and sometimes will) get deleted once the objective/purposed of it is reached.
The purpose of comments as such is documented in the Help Center:
You should submit a comment if you want to:
Request clarification from the author;
Leave constructive criticism that guides the author in ...