[notatoad]

no, the ISP's responsibility is to ensure that the majority of their customers can access websites over http/s.

and if their IP blocks are getting added to "likely scammer" lists because of SIP scams originating on their network, then it's in their best interest to do something do discourage those scams. the people working to defeat scammers aren't necessarily making distinctions between port numbers.

[iatt]

The Internet (The I in ISP...) is far more than than the web. Mere HTTP/s access is suffocating, and we should not normalize this as a customer expectation.