Yes, I feel these type of conspiracies were structurally similar, but of a slighly different composition to political conspiracy. But I think what changed is that political conspiracy became activated by the atomisation of culture and the lack of social consensus. As a result, these former examples (ufo, moonlanding, etc) now almost feel quaint and cartoonish, because they are relatively inconsequential compared to the choices people make and socially harmful actions they'll undertake with political conspiracy.

For a few reasons I personally find that the best medicine is just to nod along with these people and watch them give away their ideological hand:

a) You know where they stand and who you are dealing with.

b) They can, however rarely, be forced to actually confront the irrational logic when sharing it.

c) I think it is the compassionate thing to do, as people just often want to spout these theories as a much needed release valve. After all, people believe this stuff often because of a confusion or frustration they have with their own lives.