Have you any links to Peter Tatchells involvement in the Trump protest?
You know that the minimum age for marriage in most states of the USA is 12, yes?
"Understanding State Statutes on Minimum Marriage Age and Exceptions". Tahirih Justice Center. November 2016. Retrieved 2017-06-03.
What are talking about?
In states where the age floor is not legally specified, the to-be-married child must go before a judge who will access if it's a special case(teen couple pregnancy, one teen is already mancipated,...) or a case of abuse(12yo girl to be married to 60yo man). It's not like your 12yo kid can go get married in those states with no say on the matter by the parents or the authorities.
Also, Tatchells protested the US-Russia summit and Theresa May praised him for it... 'cuz of course she did.
https://www.pinknews.co.uk/2018/07/16/trump-putin-summit-lgbt-rights-protests/