Playerbase doesn't seem to like fighting Automatons.
The player count for Automatons is always significantly lower than with Terminids. Terminids will have 200/400k+ fighting and Automatons have like 50k or so. We cannot seem to liberate Malevaleon Creek, and all the other planets are being liberated at a slower rate.
I think the reason why is because Automatons are just genuinely harder to fight, and they can kill you at a distance. I also feel like weapons just don't do enough with them either, and they call in a crazy amount of reinfoments too.
I think it's also safe to say, they have too many things that one shot you too. Rocket Devastators, Cannons, Motars, Tank, Rocket Soldiers, the Automatons that jump to you and if you kill them to close to you they explode and kill you. Dealing with all this can be frustrating. And it doesn't help that they have some godly aim from up to 100 meters or more away.
It's discouraging getting one shot constantly, and many of the Automatons soldiers are extremely tanky in terms of TTK, and most weapons bounce off them half the time. Then there's blocking use of Stratagems, and modifierd on top. It's just not fun
Using Mechs against them is a death sentence, they pretty much one shoot you with that too
So yeah, fighting Terminids, while they have their problems, feel better to play against.