There's a difference between one company undercutting another with better efficiency, aircraft usage, accepting lower profit margins, etc...and one pilot group undercutting another with lower wages, contracts, QOL, etc.
I don't know how xjt mgmt managed to spin the books to make this into a good deal, and I don't care. I know xjet's pilot pay is untouched by this and the xjt concessionary pay/contract are very competitive with awacs concessionary pay/contracts.
As others have stated, and i agree with, xjet getting flying is only the "best of the bad options". The only good option is mainline getting the flying, but its not going to happen, ever, under any circumstances.