because variations of himself created all of those branches. He was the last one. His imprisonment enabled them to clip all the branches, and keep shyt stable.
But I could be wrong. Imortous in the comics was a Kang variant that worked with the time keepers to keep shyt stable. Marvel doesn’t follow the comics to the t so I’m just speculating.
I just find it odd that he picked those two Loki’s in particular. And he led them a moment in time that he never been to. And then seemingly wanting to be killed. He knew what would happen, but didn’t try to stop it.
How i took it was, he ultimately came into conflict with his variants. Think back to the whole self-congratulatory spiel he said they all had for each other initially. Eventually they came into conflict because of their differening motivations and the ultimate mundaneness of knowing everything
AND being virtually immortal.
After dealing with the initial variants who attempted to conquer everything, he knew his core motivation and principles at the very essence of who he is through every multiverse variation of him would inevitably lead to conflict. At his core, he's seemingly a narcissist. Also knowing he has genius level intellect and access to 31st century technology, it always would lead to him being evil.
In order to control that conflict, he established the TVA to eliminate that threat, no matter how miniscule the initial "branch" appeared to be.
Think of it like an addict, no matter how perfect their life is, if you put them in front of a drink or a drug of choice, they inevitably will show their horrible traits. Immortus is pruning the timeline before any of that can happen. Or he was doing that before the Loki's made it to his castle.
I don't think he was specifically looking for them, it was just Charlie and the Chocolate Factory-esque and they happened to have the golden ticket. They just happened to make it through all of the challenges like a flea on the back of a dragon.