Because some users are wholly incapable of ignoring and, all the more, feel compelled to comment on that which one might classify as
(oh dear, the irony) "thread hijacking", thereby expanding the distraction and codifying the takeover, RI has this fabbo feature. Is that about right?
I eagerly await a feature that will filter out any comment which doesn't mesh easily with my worldview.
All seriousness aside

comments probably couldn't live without that which they complain about and are more annoying than than that certain someone.....
imho

And, no, I don't have any particular someone's in mind here; it's a general observation.