I meant to post about this earlier, but it's been a busy morning at work today
Mike's comment comes from World Prog-Nation's post on SFAM's anniversary. Derek own page replied to him there as well. There was some discussion at the DT facebook group and even Noxon was there responding to some peoople, including myself.
The thing here is that none of Derek's actual keyboard lines made it to the finished album. If we compare the demo to the actual SFAM, Jordan did his own thing even though some of the riffs were already composed beforehand. The same thing happened with Kevin and Derek for ACOS, and I don't see anyone complaining about Kev not getting credit for that...
Now, I know songwriting credits are a lot more than just writing the keyboard parts for a few sections here and there, and if Derek actually came up with some of the riffs, chord progressions, etc, then he should've been credited... except that he wasn't and Mike was a big player in the desicion making back then, so if anything, it's by his own doing; why try to play the good guy card here then?
This reminds me of the time they were promoting SOA's first album (2017-ish) where Mike tried to "rewrite history" by saying it was the other DT members really who wanted Derek replaced with Jordan and not really himself... but he's on record saying otherwise (just watch the Score documentary). There's no point in bringing this up 20+years later anyway...
So Derek's contributions to SFAM were either scrapped (the clear Derek-isms in the demo weren't included in the album anyway), rewritten or not big enough to be considered a songwriting credit anyway. If Metallica could release two albums with songwriting credits by Dave Mustaine, even when he was already out of the band and though they hated each other anyway, why couldn't DT credit the guy if he had contributed in some significant way? Unless there was a buyout back then, as Scotty says, but then Derek wouldn't be allowed to complain anyway, since he would've signed those rights away for some $$$.