So the bad thing is the off chance that he would benefit?
Because that's a very different thing. Then this should not be about judging morals related to the thing they made, but executing punishment for a completely separate thing they did.
Then it's not a disagreement of morals, it's a disagreement on the approach you are taking to execute that punishment.
I’d be very wary of using any of his breakthroughs
Ah, but will you still use them? will you promote his breakthroughs if they help people? what if his scientific work leads to the cure for cancer?
Punish the nazi political work, promote the scientific work.
Define lack of design. You mean theming? because Linux has way more customizable theming options than the proprietary alternatives, to fit all kinds of subjective tastes.
You mean usability? it's the one system that you can rice up to do absolutely whatever you want to do to fit your workflow, you can configure any key to automate literally anything a desktop can do.
The catch is that you actually do have to get your hands dirty if you want to mold the system to your liking.. as opposed to being your own tastes the ones molding to adapt to whichever the designer of the OS decided should be the new tacky fashion or workflow.