They have met the enemy and it is them.
This is a moderate liberal trying to defend the ideology and deny that violent liberals (anarchists) aren’t really liberals. It is the same round of mental gymnastics we see with moderate Muslims denying that Islamic fundamentalists screaming Allah is greater, killing people per the Koran’s mandates, the mosque’s teachings and Mohamed’s example “aren’t really Muslim” because Islam is so perfect.
The moderates in these cases have no legitimacy because they are trying to minimize and justify the violence that they tacitly support.