I find it such a weird thing, maybe it's nice in some cases, but really this is a weird mechanism.
Phone numbers are exchanged a lot and repurposed. Most providers/carriers will likely have a do-not-use-for-x-amount-of-time bin to put newly reclaimed numbers in, but after a while, it will always be re-used. hence this kind of issue can happen.
In my country there's a place to register to disallow unsolicited marketing and other types of messaging. That's not by number you 'STOP' and hence it won't have such effects. A marketeer/sales company is simply not allowed by law to dial your number for sales/marketing, so they have auto-lookups to that registry to prevent breaching the law. translated, it's the 'do-not-call-me-registry' :D aptly named.
it won't stop phishing messages etc., but not much will. if you'd block it from 1 number, they will just use the next number..