I have seen posts claiming that rushing colonization fever and:
1: Colonizing
2: Deleting the colony by moving the pops to another planet
3: Colonizing
4: Repeat as often a necessary is by far the fastest way to produce pops now.
I dunno if that it is true but it sounds like an interesting metagame approach.
It's also a bit funny that you can colonize new planets with a race that a only populates planets without shipyards

So last game when I found the primitives in the ruined tomb world cluster and uplifted them, - I could instantly colonize new systems with them even without shipyards on any of the tomb worlds.
You can colonize with pops that do not exist in your empire now if you have a migration treaty. You need to build the colony ship manually though.
Working as intended I'm afraid.
Ships movement is way too slow anyway. I hate the kind of 4X where your fleet is obsolete by the time it reaches the front line.
I understand they chose that to incite the players to split their fleets to protect a larger territory and alleviate the doomstack issue, but it didn't work anyway.
Well it worked in a way. The AI is incapable of uniting its fleet and you are able to defeat AI empires with vastly superior fleet strength now (well when it still built them before 2.2).

Oh wait this is a multiplayer game and it is your fault for playing the unsupported single-player option.
