It's all about sex.

Being polyamorous or ENM makes you more progressive.

That all folks in non-monogamous relationships aren’t straight/heterosexual.

You cannot cheat because you're nonmonogamous.

That it's not real marriage if you're open

That you decide to be ENM cause sex or your couple is not going well.

You're just greedy. You get extra points for being pan, switch and poly. I don't like being shamed for enjoying a target-rich environm

That choosing to be nonmonogamous is purely because you are an avoidant attachment type.