This question has plagued me for quite some time. What would I do, if Hitler said “Yup, this is a good political candidate”. Certainly, the first thing I would do is pause. I would immediately back track and make sure that I didn’t miss anything about my candidate. If Hitler is evil, and he endorses this candidate, maybe there is something wrong with this candidate. Maybe I shouldn’t endorse them too.
On second thought, Hitler wasn’t an expert at everything. He didn’t know everything and he wasn’t a master planner.
A short cut that humans often take is: If so-and-so is an expert, and they believe something, then I don’t have to think about it, I’ll just take their word for it. That works in some situations. No one can know everything. It’s much more functional for everyone to know some things. However, there are many cases where we have to think for ourselves. The two instances that come easily to mind are: is God real? and Is the government good? We often take these for granted and just assume that God is real and that government is good because experts told us so.
It’s important to note that experts get used to being experts, and they habitually don’t knowledge their lack of knowledge. They continue on acting as though they know, even outside of their area of expertise. It’s possible God exists and it’s possible that government is good, but since no one is an expert, it’s important to make those decisions for yourself.