That's a complex economic question which is a straw man in this case. Just because they want to use it in a certain way, that does not make them a "systemic risk". You do have to realize that the block size limit can't be infinitely raised every time we start nearing the maximum that the blocks can take.
Agree that block sizes can't keep rising infinitely, but a simple increase _is_ a tool available to us. Core was, in my mind, at fault for not approving an increase before now. Like you say, this has been discussed for years, with zero action. There's absolutely no reason we should be experiencing full blocks / fee pressure / rushing a slightly hacky SegWit soft fork implementation (love SegWit, just don't think it's a good capacity band aid).
I'd like to see actual proposals that help solve problems.
The proposal is a temporary increase to address immediate concerns, then focus on other scaling improvements (weak/thin blocks, IBLT, a proper implementation of SegWit, etc). This sounds more sensible and less risky to me than where we are now.
I see nothing more than an attempt at taking over the keys of the main implementation (or control over developers).
Maybe the too strong influence of certain Core devs (and Adam Back, oddly) does need to be addressed. I don't see it as a power grab, more of a reset.