Yeah, there's little doubt in my mind there's a rift between them. It's not hard to imagine either. Someone like MP is well established and has multiple projects that bring in income. Ron, who I like a lot, doesn't really have any of that. At least not close to the scale that MP does. So when they start a new band thats claimed to be everyone's main band, and it folds after two albums due to no fault of Ron's, I can see why he'd be mad. His livelihood likely took a bigger hit from that change and shit gets very personal very quick when you feel like someone's decision impacts your bottom line. Just my thoughts.
I had a similar take to this:
I think the root of the problem here is the way MP tends to promote bands when he first gets into them. With AMob, he wanted to replicate the arena rock/metal thing that he experienced with Avenged Sevenfold, but it did not end up happening. At the time, when he was hyping the band up, as with any other project of his, he talked about the brotherhood, how it feels like the early days of Dream Theater. MP tends to be better at fan engagement and marketing, compared to other members of his "projects", and from my personal experience in the music industry, I have a feeling that most musicians just tend to speak their mind and fan engagement forward characters like MP are actually a minority, so his words, while for marketing and hype purposes, hold value for the other members of his "projects".
Same thing holds true for SoA. MP presented it as a "real band", "focus for all of them", again, the brotherhood. Professional music making, in a band setting, is a job. They're not doing this for fun. For some, it's an incredibly hard process. So, when someone talks like this but ends up jumping ship, it's gotta hurt a little.
Also, my guess is that MP expects full commitment, from everyone who is involved, to the thing that he is committed to at any given time. John Sykes thing ended up getting canned because he and Sheehan were ready to go, but Sykes was not etc. It seems to me that he has no trouble letting go when others are ready to go all in. When he's invested in it, it's a brotherhood, but when he isn't, he has other commitments. I remember this interview of his, during the infancy of SoA. He had said something along the lines of "I have been taking a backseat with all my other bands, but I need something that I can lead now and with SoA, Derek and I are the leaders." He just expected others to go along with it. Similar to how he expected the DT guys to follow him to a hiatus.
I understand why the rest of SoA might be bitter, barring Sheehan. He's too old to give a crap about his kind of thing, IMO.