Well, the specific reasons matter. Surely Airbnb should ban some people because of their political views (eg members of ISIS), the question is just what the line is.
What about Michael Knowles? He just went up on stage and called for "transgenderism" to be "eradicated" from public life [1]. Apparently, he shadow-quoted a Himmler speech while doing so [2].
For the safety of the Airbnb community and in particular the trans people in it, Airbnb should clearly ban him and his close associates. No?
[1] https://mobile.twitter.com/RightWingWatch/status/16320571985...
[2] https://mobile.twitter.com/GalenMetzger1/status/163218769102...
BTW what happened to the quote frequently misattributed to Voltaire is that the Nazis happened.