Suuure. "Welcome organic lifeforms. Surrender your planets and get into the (gilded) cages in our zoo". And that's the least murderous option...
Then we ofc have have "Prepare to be assimilated" and "DIE MEATBAGS!!!!!!" ones. Where only the last ones will have full wth -1000 penalty?
At this point i want to buy the pack and Butlerize them all, even though i think the Butlerian Jihad is among the top 2 stupidest things in Dune universe.
Also, what "vanilla machine empires"? We won't have any vanilla machine empires, either Utopia ascendants or this trio of lovely skynets here.
The three special civics are SPECIAL machine empires.
You can make a machine empire (a vanilla one if you will) that does not have the rogue servitor, exterminator or assimilator civic.
Thus materialists are okay with regular not overly aggressive civic machine brain worlds.
Which makes sense.