I wonder why he feels the need to take shots at Rudess like that.
My guess is that he feels inferior. He does not feel it was justified that DT fired him, he made that clear in the recent Eddie Trunk interview, so maybe it makes him feel better to criticize the guy who they replaced him with. Whatever the case, it's very childish.
It IS childish, and my feelings on the matter echo what you've said here. It is really a shame, because he does have a point -- it was NOT justified that DT fired him. But, DT (including Mike) wanted Jordan first, and when he was available, they shat on DS to get him. So, I do understand DS could harbor some hurt feelings toward DT. But obviously, he's cool with Mike, and was cool with the rest of them to perform with them post-firing.
Personally, I would have preferred they stuck with Derek on keyboards, as Jordan isn't my cup of tea. But it has been 20 years. I moved on, and Derek did too. If Derek is serious about all these slights, and it is not just him trying to be funny, then I'd say this "reunion" with Portnoy is the worst thing for him. Because all he is doing is destroying two decades of professional goodwill he built by staying classy until this.
I've pre-ordered Sons of Apollo. I am looking forward to it. But if this is how Derek and Mike are going to be on social media and moving forward, I'll have to reconsider supporting them. I've done it for bands I was much more invested in when I felt like they said or did things I don't approve of, and so I can easily do it for a brand new prog band I've only heard snippets of (I have not listened to the two songs).
Success these days is built on goodwill with fans and getting them to come out and see you perform. Take the Queensryche fallout. Don't tell me the turnout of that affair was based just on the lawyers. It certainly wasn't. Public perception, which was driven by social media and message boards, was a key component in that whole affair.
So, if Sons of Apollo wants to do well and make a name, I think DS and MP may want to reverse course a bit, and stop sinking themselves before they've even left port.