> #1 seems practically impossible to do, considering that the definition of what a crime is tends to vary between jurisdictions.
Alleging that someone has done something that happens to be a crime aren't a problem, the problem is wilfully alleging crimes outside the court system. The overwhelming majority of the posts that cause these problems either explicitly claim that someone has committed a crime, or explicitly claim that someone has committed an act that is well known to be a crime.
> #2 is already true in some cases
Not really in the US AFAICS? Certain narrowly defined groups are protected against being denied service by private businesses, but there's no broad general protection.