Out of curiosity, if I may ask: where do you live?

(Because I've never heard of such a thing.)

Los Angeles, but I've had similar clauses everywhere I've lived and with multiple USPS (Starry, Charter, Time Warner, Verizon, university housing, etc)

While my ISP, Comcast/Xfinity, does have a "Business Plan" that allows you to have a server, the normal residential plans prohibit it.

Ah that makes more sense. Also very sad. Hopefully as fiber becomes more prevalent that will become less common.