Yeah, I think Thanos was used to promote the genocide plan in a revelation of the method kind of way. His character is even different from the comics. His goal in those was pleasing the goddess of death if I remember right (?) He is batshit crazy, while in the movies, he is portrayed as a deranged visionary of sorts.

Realistically, we don't suffer from overpopulation but wrong distribution of resources, with the corrupt oligarchies not allowing there to be a solution to that as well...

Hydra is also a good representation of any evil elitist group too.