I don't think same sex marriage caused this. Firstly because there are countries that have embraced transgenderism where marriage equality doesn't exist. Secondly the groundwork for much of what's happened was laid decades ago. Orgs like The Beaumont Society/Press for Change in the UK have been around for a long time. We had the Gender Recognition Act (2004) years before marriage equality, in fact one of the main reasons the GRA exists in the UK is because the government at the time did not want to introduce same sex marriage.

That said organisations like Stonewall have taken advantage and accelerated things due to having a vacuum post marriage equality. It's provided them with a new cause and new income stream. So I can see why people conflate marriage equality and what has come after.

Re the mental illness aspect. I don't necessarily think it's a problem to have removed the T from the DSM just as it wasn't with gay. For me it's a case of present outwardly how you wish but stop pretending people can change sex and that there are no consequences to that lie.

As a comparison it would be like gay people decades ago rather than fighting for acceptance of reality e.g two men can be in a relationship and that's fine, insisting their relationships were actually heterosexual despite the evidence of our eyes.

I really don't see how in 30/40 years the concept of gender ideology will have survived all the inevitable casualties. Things are pretty bad now and a hell of a lot of people are starting notice. Are people really going to be discussing in decades to come about how it's so great that no females compete in sport now? Will they reminisce happily about how backwards it all was when AFABs used to win Olympic medals? I hope that's not the dystopia we have to look forward to because it's not a world I want to live in.