Seems like fair play to me honestly and can only really be elegantly dealt with on yelps end by tracking who users are and showing them reviews of people with similar preferences.
The logical approach to me given the current system would be vax passport proponents to penalize bars for NOT requiring such passports in the reviews. I think these reviews are fair game but the knife cuts both ways.
Not that I use Yelp since they're extortion racketeers.