Catholic teaching no more “led the way to homo marriage” just because many people support it in largely Catholic countries any more than Christian teaching led the way to the homo victories in the USA. It is the deviation from and rejection of those teachings.
You can ask why are so many Catholics deserting biblical ideas of morality. You can’t say biblical teachings on morality caused the desertion. In your post you seem to be presenting an argument that Catholicism has failed. That may be a fair question, just as Christianity in the west has generally failed. There are probably a variety of reasons for the failure. The Bible teaches we are always battling sin and our sin nature. History teaches that the war against Truth has suffered many defeats. That does not mean that the teaching caused the failure or even led the way. It is the enemies of the teaching that cause it to fail.
I’m not Catholic and I have many issues with Catholic doctrine. I am speaking of their basic moral teachings. Even there I think they are weak in some spots. Still, where they are right, right teaching does not CAUSE wrong practice. Rebellion against right teaching causes wrong practice.
The issue, as I see it, is not their moral teaching in these areas. Rather, I see it as the bishops' social teaching, which I expect to be uniform from country to country as they claim to be of "one church", has poisoned the "moral teaching" so badly that Catholics will jettison their pro-life stance and vote Democrat without blinking an eye. Eight years ago, Catholic FReeper "all the best" gave his excellent diagnosis of the problem, which holds up even moreso today:
"Show me just one Catholic bishop who will speak up against coveting your neighbors’ goods. That is why Catholics ignored the Bishops on abortion. They know abortion is wrong but overlooked the Dems on that point because those same politicians pandered to their covetousness. Same for protestants and evangelical pastors, leaders and activists. American politics and government at all levels is driven by government-mediated coveting. Until the Church takes a stand against this we can expect to sink deeper and deeper into socialism and, oh yeah, abortion."