Actually the surprising thing is getting involved at all. Right now even whiff of support for Trump is toxic.
This is why he's winning. People are fed up with the PC police and their purging of anyone with "toxic" ideas.
Edit: It seems you mean career toxicity. Thiel, being able to write his own ticket, would founders really be unwilling to work with him on the basis of his political positions?
What will happen to Christies career when Trump appoints him AG?
http://www.nj.com/politics/index.ssf/2016/03/christies_trump...
So Trump support tends to be underwater. People don't like to support him publicly.