'We agree, except for this case.'
'Freespeech: unless it isn't.'
It's with the same incredulity that Josh Lyman asked a gay congressman on The West Wing how he could caucus with a Republican party that viewed him as a second-class citizen; less than human.
Improving inclusivity and diversity necessitates excluding racists, sexists, bigots.
This kind of black and white vitriol is what has lead to this election being as awful as it is.
The real issue is that Trump and his campaign have actively tried to appeal to the -ist nature of people for political gain. And Thiel's donation is a tacit approval of either the tactics or the philosophy itself.
Trump is certainly not alone there; appealing to the "-ists" is the foundation of every campaign.