I have to imagine that WECT is a holdover from when markets (ADI/DMA) were not as clear-cut as they are now, when out-of-market stations were seen as desirable due to schedule diversity and because that's all there was as an alternative to local stations (no satellite delivery yet), and when, as I noted, WECT billed itself as covering both cities with a somewhat centrally-located signal. There may also be historic viewing habits that die hard.
WECT shows up in the FCC's significantly viewed stations list, which is horribly outdated, for both Cumberland and Hartnett counties. It really doesn't matter, though, as cable is a dying industry, satellite and OTT providers typically don't offer out-of-market stations, and local newscasts can be pretty much had on demand online, either live or recorded.