Fantasy Football is important to a lot of people. Sometimes a little too important.
Cardinals wide receiver John Brown was "active" for the Browns game, but didn't see a minute of playing time. As you can imagine, those Fantasy owners who started him were a little pissed. Head coach Bruce Arians replied to those upset with him for not playing Brown.
Brown personally responded to some of those angry owners on Twitter, and they probably wish they hadn't said anything at all.
The lesson here is that you can start or sit whomever, the Cardinals don't care about your fantasy teams.