Earlier quoted context omitted.
Many interested in mitigating abuse.
They can report the domain to the registrar. Doing something with WHOIS info sounds more like a cloak and dagger fantasy. In reality, having your personal info in your WHOIS sets you up for abuse.
Tying together multiple domains to a single authority (as here) is useful.
Essential? Dunno. But definitely useful.
Source: used WHOIS extensively in abuse mitigation and reporting.
Registrars tend to DGAF, though I suppose blanket blocks of all domains from a given registrar, practiced widely enough, might have impacts.