not so against any kind of increase in the max block size
The Bitcoin Core capacity roadmap includes several block size increases, including the immediate term segwit proposal that many people are actively working on (and which has a testnet)-- which increases the capacity to fairly close to Gavin's latest proposal (which is not BIP 102).
'immediate term' , no one knows what that means exactly. 3 months? 6 months? 18 months?
This would be more immediate, simpler, and arguably more robust and less risky. What does core have against it?
The community has been screaming for bigger blocks. If core won't accept Gavin's proposal, it means
one of three things:
1. They don't care what the community wants (despite their pleas for consensus).
2. They think they know what is best and are too stubborn to accept anyone else's priorities.
3. They have an alterior motives.
Could be a combination of all the above.
Mr. G. Maxwell is a key developer on Core in addition to being a founder of Blockstream.