I hold leftists to be 95% responsible. They are responsible for creating, perfecting, and setting these concepts and ideas into practice; sort of like how it is dr. frankensteins fault that his monster killed someone. Your mention of political correctness and its connection to the subject at hand simply serve to underscore my assertion.
While I agree with everything you've said above, I also think a lot of it has to do with the way people can and do make money by exploiting the homosexual lifestyle and shoving it down our throats. A great example of that is the popular TV show "Survivor" where in EVERY single season at least one cast member is gay, and oftentimes a flamboyant flaming queer.
Now is there an "agenda" behind all of that, or do the producers realize witnessing such a farce and spectacle make for good ratings? Meanwhile millions of families sit down together every week and lots of kids are indoctrinated that such things are "normal".....unless you are in my household where we just laugh at and pick apart the hypocrisy of a lot of these people.
Granted, I don't spend much of my thought process aware of who is left/right or conservative/liberal....so perhaps all of their executive producers and network CEO's ARE in fact leftists , but perhaps a lot of times there isn't any pre-planned endgame in all of this....instead just chasing the almighty dollar with the resulting effects being our morality and sets of standards being flushed right down the toilet in the process.