Here it is.
You know how incapable of admitting he was wrong trump is? IT WILL NEVER HAPPEN!
Well his supporters are equally incapable of admitting they were wrong about him and so that is the complete and total WHY of their sticking by him no matter what. If they were to admit he was wrong/did wrong they concomitantly would be admitting they were wrong/did wrong. They cannot do that. They are as rigid as he is in that regard. So they will not abandon the sinking ship. They will go down and drown with him. That is preferable to them than admitting they screwed up.