Without some sort of underlying religious ideology to neutralize being concerned about the likely outcome of hellfires dropped on you from 20k feet if you kill American soldiers, I can’t see many stepping up.
Even if they are aided by others, they would still be fighting for THEIR freedom, in THEIR land.
(distinguishing the good guys from the baddies becomes easier, when you strip away the fluff)
A "proxy" is someone who primarily serves someone elses interests first. Their own interests are subservient to that (if they come in at all).
Venezuelans who may end up fighting for Venezuelan freedom to rule themselves as a soveriegn free nation, with the right to fully benefit from THEIR own natural resources, are NOT proxies of anyone. Regardless of who helps them.
When you're a closet imperialist who thinks nothing of stealing other peoples land, resources, dignity & even lives, then everyone opposing you starts to look like a terrorist, an insurgent or a proxy.
The issue isn't them. Its you.