You can't balance for all maps. If you change something for map X and Y, then map A and B will desire another change, etc. And I don't recall saying they're not part of the game - they are. Just a unique part that you reference to as turtle maps. Why would we balance the entire game taking into account a specific genre of maps? Instead, make a balanced mod for those maps that fixes specific problems, whether that is hives or something else.
I'd also like to argue that isis is significantly less of a turtle map merely due to its size: 10x6 against 20x12 (estimation). Hence early raids are a lot more applicable: a bomber doesn't have to fly for two minutes to reach its target. In Gap raiding of the 8x core mass extractors is effectively impossible if both teams play decent. Therefore it is a lot more turtle-like.
And I'm not saying you made things up and you certainly didn't introduce that concept: I introduced that concept with an extensive post a few weeks back. Not balancing for what can happen in a casual map is quite common in any game. They are all balanced around the competitive section of the game and the casual players just follow along.