I think it goes back to when Joe was negotiating with Spotify and eventually left. CTG and Andrew Shultz started questioning if Joe does good business or knows how to do business. They questioned whether he was worth what he was reportedly asking Spotify for.
Joe shitted on Shultz and left that alone. But he and CTG at it every since. He said CTG shouldn't be trying to shit on a black podcaster trying to move the culture forward. That had he got the deal he was asking for that it would ultimately help all black podcasters
It also didn't help that when the shit with Mal and Rory popped off a couple years ago that clip of Charlamagne on the show when it was still I'll Name This Pod Later resurfaced with CTG predicting exactly how their breakup would happen over suspect business dealings. That going viral again and the subtle shots brought it back up again. Joe and Mal were on a "The Breakfast Club hasn't mattered" kick but Joe really been throwing shots since then