Remember everyone forgot about all that after the cracks in time storyline.

What everyone is missing is that the Doctor never knew she changed her mind and did some good. As far as he knew she laughed him off and left with Simm.

We also know that Evil Morty is a master manipulator and emotions, especially coming from a Morty, could potentially ruin Rick C137. Evil Morty can also “disguise” himself to pass off as our Morty, being a damn good actor, and HE KNOWS how much Rick cares about Morty(s) so he has a side to play there.

Another thing that I read someone say was that maybe Evil Morty was killing all those Ricks back in season 1 because his plan was all along to win by Morty vote, so he was creating a unbalance in quantity. I don’t think Mortys were allowed to vote, though.

He also has to go after them as soon as possible because they (or Rick really) were the ones who collapsed the previous government in the first place. Though the thought that C-137 Rick was directly responsible for Evil Morty’s rise to power is mind-blowing.

I realised who he was the moment someone asked him who his Rick had been/where he was from, just because I’m convinced it’s our Rick and they have some history.