Strongtowns is happy to follow the money and incentives on all sorts of other issues. Why do they just throw up their hands and say "it's the developers" on this issue?

Developers don't do anything that costs money, like set up an HOA, without a reason. The developers create the HOA because you need your >1ac residential development to pass stormwater permitting. While you theoretically could make each individual .25ac parcel you're putting a house on compliant it's infinitely cheaper to just ignore all that, grade everything toward the road, dig a ditch, send the contents of the ditch through your stormwater treatment features, build in a little margin to those items, show the permitting authority the numbers that prove it passes with flying colors and when some jerk says "but what if X Y Z changes" you point to the excess you built in and tell them to GFY.

Now, where it really gets evil is when you start really pinching pennies or where the rules change over the course of the process making your numbers not work. Say you've got a lot of grade, a lot of rainfall, a lot of stormwater you gotta "treat". Well, you start adding rules to the HOA. Require certain parts of the lots remains grass or planter or whatever. Disallow patios, but do allow wood decks because the municipality considers those pervious, etc, etc. Or maybe the results you've got are marginal but you throw the bureaucrats a bone by saying you'll disallow car-ports and sheds in the HOA rules to prevent people from adding impervious surface. Or maybe you're uphill of some wetlands but not close enough to be regulated by default you promise to disallow working on cars and require people pick up their pet waste and not use lawn fertilizer or some other laundry list of certain things in order to make the local town's wetlands people comfortable not raising objection and claiming jurisdiction.

And of course, however these rules and plans shake out, the HOA is responsible for implementation in perpetuity.