Okay, this is actually more complex.
First off, why is she uncomfortable? Did he harm/molest her or do something else to her that you are unaware of? If the answer to the reason she is uncomfortable is simply because he doesn’t share her political opinions, then that’s insane.
Second, who is paying for the wedding? If she paid for it, she controls the guest list, but if you paid for it, then unless she was molested or abused by said Uncle, you should have told her to grow up that he is family and he is coming.
Third, to expect a gift after being complete slighted (assuming he has not harmed or molested her), shows your daughter is a horrible human being, and that you raised a brat....
Given you capitulated to her desires, (unless of course there was some history of abuse/molestation), its pretty clear to see how she wound up that we.
I wish her husband good luck, he’s going to need it.
If he had molested or harmed her in some way that made her feel uncomfortable, then she has ever right to not have him attend, but she should not be expecting cash after doing so.
That’s far better than the response “Amy” gave.