I posted a request for information regarding the matter. The reply I received from @markymark was provided there.

@iflagtrash and @abusereports, both sock puppets of @berniesanders, flagged the above comment. Since he has a lot of Steem on both those accounts, he reduced the value of the comment nominally to censor it. I use Steempeak, and not Steemit or another frontend to use Steem, so the comment is not greyed out to me, because Steempeak handles flagging a little differently, or perhaps because it's my own comment. I don't really know why it isn't greyed out to me.

I don't know why you are unaware of the flags on the comment. Partiko has been suggested to not reveal some flags, but that's the only interface I am aware of, and only one user has told me that about it, so I don't know the facts of the matter, since I don't use Partiko.

This comment will also receive two flags from Bernie, and probably be greyed out as well.