People can be smart and respectable in one domain and stupid in another.
But a person cannot be both respectable and disrespectable at the same time, I find, although I'm afraid now we might be disagreeing rather about words than ideas. Respectability, to me, is a compliment to somebody's set of values.
I find it troubling that we should censor (explicitly or otherwise) someone on accounts of his respectability. I find this especially true when the source of disrespectability stems from an unrelated topic.
We can both condemn the stupid/wrong behavior and celebrate the intellectual achievements. The point is that we shouldn't hold back our praise of the latter on account of the former.
This is a typical false-dichotomy that plagues contemporary discourse around social justice and various *isms.
If we abided by your reasoning, the US wouldn't have a space program.
The other matter is rehabilitation. Whether he should be allowed to apologise at some point, say that he made a mistake, and be welcomed back, is something that you cannot decide for everyone. It's up to your personal beliefs, in particular your religion. Everybody needs to determine that for him- or herself, in my opinion.