Ruth Hunt was indeed the main reason Stonewall added the T (and then the rest of the alphabet) to LGB. Ben Summerskill, her predecessor, led Stonewall from 2003-2014 and always resisted pressure to do so.
When Ben left in 2014 Ruth was promoted from Head of Policy (if I recall correctly) to lead the organisation, and she very quickly reversed his decision and joined the T onto LGB and the rest, as they say…
So even leaving aside all the other reasons why her reverse ferret is utterly astonishing, SHE WAS ACTUALLY IN CHARGE OF STONEWALL WHEN IT DECIDED TO START CAMPAIGNING ON TRANS RIGHTS, reversing the much more sensible decision of her former boss to stick to LGB.