Long story short she is a highly controversial figure in LGBTQ history. Her vote to decriminalise homosexuality is quite complicated. She was one of the few MPs from her own party to vote for the bill and considering that she was a rising star in the party the decision seems like an odd one since it would seem more logical to keep her head down and vote where the whips told her. Off the top of my head I cannot remember what convinced her to change her mind. She seemed to have reversed her position in 1987 when she made a fiercely anti-gay speech to the Tory conference and allowed through Section 28 which banned positive public discourse on gays, what today is called "gay propaganda" in Russia. Yet she seems to have been relatively tolerant of gays in person, for instance she appointed the Earl of Avon minister for the environment even though the entire party knew that he was gay. As for AIDS it is notable that she did not follow the line of some of the right wing press and denounce it as a punishment for sins committed or whatever. Instead an "AIDS: Don't Die of Ignorance" campaign was launched. Form the beginning it was treated as a public health issue.