Bigger problem is at least two of the more well known AV solutions are badware. My enemy #1 in this regard is McAfee, but recently (front page now) Avast seems to have upped their game considerably.
According to stopbadware.org a badware is a "[...] software that fundamentally disregards a user’s choice about how his or her computer or network connection will be used."
This in addition to causing general issues. (On at least two occasions have I fixed what weird computer problems just by removing McAfee.)
Oh, and yes: scammy click-by-installers when you try to install other software.