I dont, and to my knowledge never said, that someone can only care about one. The problem is confusing cause and effect, and being unwitting pawns for the other side. Let me explain by using one of the examples in the OP, nazism:

1. Assume that gig economy is caused by nazism
2. Gig economy is a big problem, therefore nazism is a big problem
3. By chasing nazism everywhere and aggressively trying to stamp it out wherever gig economy is seen, we will fix gig economy

And you can replace nazism with any of the other causes mentioned, white supremacy, fascism, whatever.
This reasoning pattern isnt productive though. Even if nazism is a big problem where you live, fixing it wont solve gig economy, and chasing ghosts wherever you see gig economy just leads to conflict between our side of the class war.
I mean just look at this thread. Look how many people are just calling me names! This is how entrenched the problem is.
If you want to fix fascism, fix fascism. If you want to fix gig economy, fix gig economy. But if you want to fix gig economy, don't try to fix fascism, white supremacy, and nazism wherever you see gig economy.