I hear you, but it was the best decision you could make at the time, from your perspective.
You can't go through life regretting decisions that were good at the time.
Not wanting to forget your vote (whether for Trump or HRC) is not necessarily a reaffirmation of the individual voted for...it could be just the reaffirmation that the vote was the best vote you could make at that point in time...not wanting to forget a vote may just be a reflection of a person's personal view that second guessing past decisions like that is not helpful. You can learn from such decisions without wanting to forget them.
For me, if I wanted to forget my vote, it would mean that I decided I made the wrong choice at that time. I don't think I did. So, I don't need to forget that vote. That doesn't mean I'm a big Trump supporter now, or I like everything he does. I don't. But, I still think I voted for the least awful person from my perspective. It was the best decision I could have made at that time, so I made it. No need to feel bad about it.
Now, having said all of that, if the Left predictions of Trump created concentrations camps were even remotely coming true, I might want to forget my vote. So, I guess there is a counterpoint. Thankfully, that was all insanity.