As with many of these types of laws in California, I suspect they are deliberately vague.

If people/businesses have to guess at what's compliant, then they will often choose the most restrictive form of compliance out of an abundance of legal caution.

Possibly even unconstitutionally vague.[0] If a law requires someone to accurately predict the future actions of large numbers of people they've never met, then that seems (to my non-expert understanding) like an unreasonable burden on citizens.

[0] https://en.wikipedia.org/wiki/Vagueness_doctrine

Frankly put, and regardless of your personal views on the subject - if the California Pro-2nd Amendment folks haven't been able to get anywhere with this "Vagueness Doctrine", then neither will website operators.