A person can make a mistake, realize they were wrong, and change their mind. This is the basis of personal growth. Insults are not an appropriate response. This only promotes division when you should be looking for allies.

There are many examples throughout history. You can read about Erica Chenoweth’s 3.5% rule for the general phenomenon. Regime changes are unusual, but not unheard of. It happened with Eduard Shevardnadze in 2003.