Based off your article, I feel like you have a disconnect between characterization and the banality of evil.

Just because a character is relatable doesn't make their evil paltry. Thanos is evil and his actions are in no way paltry. We understand why he's doing it, and it seems reasonable and he can justify it. We understand that justification, but the result and method are undoubtedly evil. Which makes his actions even scarier because he's thought it through and done the calculus.

I am bringing up the Nazis, sorry, but they provide the best analog to real life and thanos. The nazi's had strong justification for their genocide, they were making the world a better place, like Thanos. Individual Nazi's can be relatable, like its recorded that the Nazi's were "normal" and relatable at a personal level. But committed horrendous crimes. Can you say that the Holocaust was paltry, because we can relate to those that perpetrated it? Because from the view of the Nazi's their actions were justifiable? That they had a "good" reason to kill jews? Hell no.

Another example is Ed Kemper, he was extremely well liked, had a good "character," too him, and made friends with guards and cops. He also had a justification for his actions. Yet was his evil paltry?

Also, you seem to be making an ends justify the means argument with Thanos, which....eh? You want to go down that road?

Thanos' plan is downright evil. You take any system, deontology, utilitariasm, virtue ethics, etc. He's evil, not just his "indiscriminate killing," but all his actions to get to his goal of mass genocide for the "greater good"