Just because mainline pilots blessed it does not make it inaccurate. The DC9 has basically the same MGTOW, and wingspan as the CRJ900 and the AA E175s (but a shorter range due to straight turbojet engines). Are you telling me that you'd be ok with Compass or any other regional flying the DC9? Or 737-100, or 717? Because flying the 175 is pretty much that. Even in today's pilot shortage Scott Kirby thinks he can convince United pilots to relax scope with the Cseries. And in AA's last negotiations there was talk of scope relaxation.

Sure as regional pilots we don't get a vote on it now, but guess what as people here say we're going to be there in the next few years, the ones voting at our career carriers in the future. So saying that another regional is stealing flying from another regional is only half true. At the end of the day every regional is doing the work that should be at mainline.

We are going to be the pilots that determine the future of the regionals and scope. Management at the legacy carriers still want to keep costs down
Even with rising compensation at the regionals it's still cheaper than a Captain at $160/ hour or an FO at $86/ hour.