lol, let me guess; you're a liberal, right?
Um...far from it Elroy.
From the OP:
A co-worker, whom I greatly respect did something I cannot fathom. ...
So I thought I would bounce it off some folks here and see if I am way off base here or if she might have been to quick to avoid a socially awkward situation. .... I was stunned at the waitresses behavior .....There is no way in hell I would have paid for that stuff, period, nada, zero, null chance at that whatsoever.
There's a reason you respect your co-worker: She is not an asshole in social situations.
Has nothing to do with her politics.
I now have a question regarding the type of person the OP respects. They probably embarrassed the poor waitress, sitting around critiquing her performance then walked away without tipping.
They all need a life if $7 is so important to them. Of course she's an asshole in social situations or she would have spoken to the manager quietly and not ridiculed the waitress in front of the other diners.