What evidence do you have that that is true? Looking at his career experience on Wikipedia suggests the exact opposite. Not to mention it's a win for LGBT causes which he is known to be a supporter of.
It's a win for LGBT causes to ally himself with somebody who believes in Conversion Therapy?
[Edit: I meant Trump, and I was wrong - see below. Technically Thiel is also allied with Pence, who does believe in Conversion Therapy, but that wasn't who I meant. I apologise]
Trump has never said he believes in conversion therapy. That is Pence, who is the vice president a position of little to no power. If you are advocating that you shouldn't ever associate with anyone who has a wrong idea about something then I think you are really wrong. Engaging people is how you change minds not shunning them because they have a factually incorrect belief or disagree with you.
However, from the same article it appears that Trump has vowed to sign the FADA, has said he supports North Carolina's anti-LGBT law, and has said he would strongly consider appointing Justices who would overrule marriage equality, which seem like legitimate causes of concern for the LGBQT community.
[Edit: Arguably Thiel is allied with Pence as well, who HAS advocated Conversion Therapy, so what I wrote was technically correct, but I did indeed mean Trump when I wrote it and I was wrong]
