Yes, since he was already convicted and jailed after the attempted coup in 1923 and released early for administrative reasons. Also, Hindenburg should have refused to appoint him since Hitler already showed is true colors at that time.
I lean toward this. You can't have a special "smarter than the rest of us" class that just decides who is and is not dangerous to lead a democracy or a republic ... or your government is just fundamentally neither. Sam Harris-type ideology is horrifying and gross.
With that said, it's perfectly reasonable to have a law on the books that prevents anyone previously convicted of trying to literally overthrow the government from running for government, lol.