Which villain has more justifiable reasons to be one?

I always thought Galactus was neutral and just needs to live

I would say the same but he's seen as a villain by many people.

I think the same @ThorMathews

There is also Helmut Zemo (MCU)

Also, Baron Zemo from the comics. He sided against CA, that is true. But if he didn't, he could've further ruin his countries's reputation. He then wanted to kill CA so he could have revenge for his scars.

Thanos is one of the ones that more justifies his purpose also for me, nice list