By banned do you mean your AdSense account is deleted or locked so that you no longer have access? This the first I've ever heard of such a thing. If this were true my AdSense account might have been locked long ago.
I post videos all of the time not only to my personal Facebook page, but also my business, or YouTube channel's, Facebook page. I don't think I've had any issue with my AdSense account. Hold on a minute. Let me slide on over there and check.....
.....Nope AdSense account is still there and.....oh look.....I still only have $1.93. Yeah me! Someday that shall be more.
.
I'm not even sure why YouTube would want to do such a thing. I mean I totally get that Google sees Facebook as direct competition with Google+, but if you've monetized a video and a viewer watches it through your Facebook link it would still generate ad revenue and make YouTube some dough.
Also, when I open the Creator Studio app on my phone I can see that Facebook appears as an external source for views.
It sounds strange to me that YouTube would do something like this, but maybe it's a new rule they've totally created more recently which coincides with all of the big changes they've been making.
Other than that I really don't know. Sorry, I hope some of the information I've provided above helps.
Take care my dude!
.