I don’t see why you phrase it as a government centric angle rather than an individual responsibility angle. We are the ones who held the indoor gatherings, not NIH.What’s more interesting is that people in stay at home order states were just as likely to test positive after a birthday than those without. It points to one of the reasons the us lockdowns were ineffective: they didn’t/couldn’t control against these types of informal gatherings.
This is more of a time to look back and say “I personally should not have done that.”. It is sadly dependent to say, “That was a bad idea. Why didn’t the government stop me?”