Not legal for them to do that. I'd contact the FCC and file a complaint. Cable companies are required to have local channels through the cable lines whether you're a subscriber or not. You sure your TV isn't set to antenna? It still needs to be and you still have to do a full channel scan.
Just tried to hook a cable straight from the wall outlet to my small TV, get nothing but blue screens on both cable mode and antenna mode, even after a scan. Well that's not completely true for some reason channel 16 on cable is the color bars.
I remember last year or the year before Cox around here kept putting out that they were going to cease offering the analog signal of their services, including the broadcasts(here those are channel 2, 10, 13, 43, etc). When they started this process one by one channels disappeared from the analog signal, instead giving way to a splash screen saying the channel was only available vie digital, which required a box. Think it was May of last year the last of the analog channels were finally removed, and now you have to have a box of some type between the wall outlet and the TV to get anything at all. If I try and view channel 10-1(NBC) or whatever via the wall outlet only, my TV displays a "scrambled" message.
Also refer to this:
http://www.courant.com/consumer/bottom-line/hc-bottom-line-cox-all-digital-20141215-column.html
A Federal Communications Commission ruling in late 2012 allows cable providers to shut down unencrypted basic channels — major networks ABC, CBS, Fox, NBC and PBS, and public access. Unencrypted analog signals were easily shared (or stolen) by wiring multiple televisions from a single cable feed using a splitter. The encrypted digital signals are unwatchable without a decoder box.
Cable companies, as part of the FCC ruling, must offer basic-cable customers who have no set-top boxes in the house — often the poor or elderly — either a set-top box or, where applicable, a CableCard free for two years. Medicaid recipients get a box at no cost for five years.
So while there are options to help ease the burden for certain people, cable companies are no longer legally required to offer CBS/NBC/ABC/etc for free straight through the wall outlet.
What? That's completely wrong. OTA digital broadcasts still require compression. There's only limited bandwidth in the EM spectrum that's available to broadcasters.
Like all digital media, the quality of OTA digital broadcasts comes from the codec used e.g. MPEG2 and the bit-rate. You can have HD broadcasts with low bit rate, and you'll get compression artifacts, as you would if you watch a low bit rate BD rip.
What I mean is the signals go through more compression on a cable system than they do OTA, because those cable lines host far more channels than the OTA spectrum in any given city.