Due to recent events, I would like to observe that when people are invested in another person, they tend to be willing to defend that person far longer than other people think is reasonable.
Please be kind; it appears that this is completely natural.
It would be tempting to say, “if you support him now, after this, we cannot talk again”, but really they are just falling into a variant of the sunk-cost fallacy; they have invested so much of their own personality in supporting him that it is difficult to abandon it.
Some never will; yes, they are lost. But be kind to those that abandon it and accept that they were wrong, even if they wont be shouting it from the rooftops.