I'll judge them all the same because it's not illegal to give someone feedback. Unless you have discriminatory hiring practices in which case the judgement holds true, or your legal team is so far up their own and everybody else's ass, the judgement still holds true.
Partly the problem is "the system" people created for themselves. At some point people started suing employers because of some really contrived reasons so employers became very, very careful.
If there is a big company that hires a lot of people and this is managed by many HR stuff, it is much cheaper and safer not to give any response than go through every rejection response to double check if something seemingly innocent cannot be interpreted as "discriminatory practice", rightly or not.
The requirements to open yourself up to a discrimination lawsuit are fairly high.
Legal doesn't have 'interview experience - net promoter score' or any other interview quality metrics as one of their KPIs, so they're happy to mandate the nuclear option because it gets work off their plate.
It's less about what the laws say and more about what the consequences of not following industry standard would be.
If you explicitly flout standard and as a result get sued for violating one of the related hiring/discrimination laws, your investors may have a good case to sue you personally because you didn't act in the best interest of the company by opening your company up to that extra risk for no tangible benefit.
That's not a reason to let them off the hook, because they control the rest of the experience. If they can't give feedback, then they shouldn't have a hiring process that asks for such effort from the candidate.