I too am baffled by this move. While all we see are the 6+ numbers, they are large enough that FM 100's demos have to be excellent. And WMC-FM's demo is an attractive one for advertisers.
If the rumors I had heard are true, part of the reason this seems so baffling may be because this was a Plan B that wasn't ever supposed to happen. The rumblings I had heard were that Cumulus would contribute a station, or a few stations, in this deal and would ultimately end up with WLFP and WTSS. As Cumulus would've contributed an underperforming station in a much larger market and the intellectual property of both would've ended up with Cumulus, both Cumulus and Audacy would've also ended up with some additional cash.
The new CEO at EMF may have decided airing K-Love in said much larger market didn't make sense given its saturation with CCM stations and that it's one of Air 1's most successful markets.