As far as the mechanics, you are going to have them anyways because otherwise you don't have growth at all. That is their primary purpose. Why count them towards dragging you down when they're the only thing holding you up?
Sure you need them for growth, but if all space is filled up, you couldn't simply take them away, cause you would lack their amenities. They are the best maintenance drones one could have with base 5 production. So I see them more like maintenance drones (or Jobs) with the growth mechanic tied to them, which in turn means, I just have to pay minerals for a new pop and actually don't need any additional pop for that. This is also more in line with bio empires, who also don't need any pop for their growth. From your perspective it would mean, you need less maintenace drones but have to pay heavy for growth with pops.
In the end it's just a matter of the view, but which might lead to different interpreations.