Well no, not really. They are just stating the fact that the update will almost certainly break their mod (and many others tbh) and just want time to fix it so even unexpierenced modders can enjoy it. They also say they are excited for Bethesda's update since they love FO4.

“Before you grab the pitchforks to go after Bethesda or tell us that we’re idiots and you know how to stop the update – remember, that’s you know how to do it, not the collective. This is a collective project; we want everyone to have the past four years of work to come out and be the best mod possible for all of our followers."

“The fact that Bethesda is keeping what is an old game updated is honestly a great thing – many members of the team are very excited to see this,” he notes. “On the technical front, being able to play Fallout London with the new potential engine improvements and the performance upgrades is fantastic. It’s going to mean that we can push the engine even harder than we’ve already pushed it. This is all going to be a boon.”

The Bethesda never changes bit was a joke that in context seems like he means it in a positive way.

"Bethesda. Bethesda never changes,” he concludes with a smile.

“Before you grab the pitchforks to go after Bethesda or tell us that we’re idiots and you know how to stop the update – remember, that’s you know how to do it, not the collective. This is a collective project; we want everyone to have the past four years of work to come out and be the best mod possible for all of our followers. We want to incorporate this special mod that we’ve created for everyone.”