I think it makes sense. They boosted stack overflow because they think it's often relevant, but not necessarily always the best resource. But now it's always #1 when oftentimes there is a clearly better resource. They just wanted it to be #2 instead of #10.

Basically they are wishing the boost feature had room for more nuance.

There is a bit more room for nuance, you can pin domains, which places them above "raised" domains. I've pinned MDN and official documentation sources, raised StackOverflow and blocked SO clones. It works well for me but YMMV.