It sounds like an apartment building restriction, not a Spectrum restriction. The building wasn’t run for ethernet so they just put in wifi with a single modem for the building and called it a day.
I fairly regularly work with someone who, in their organization’s alias scheme, was given the email address of an 80s cartoon villain. It rules so much and I doubt she’s even in on the joke.
It sounds like an apartment building restriction, not a Spectrum restriction. The building wasn’t run for ethernet so they just put in wifi with a single modem for the building and called it a day.