Does appear a bit ridiculous... so Either there is some unmentioned other reason, some cultural difference, or just an excuse to back out... it really doesn't make much sense in context.
Ya because they realized they were duped into adopting SW in exchange for something they could do anyway without blockstream permission.
That is very insulting to the Chinese miners and f2pool... I seriously doubt they have remained ignorant of segwit and its implications that have been so openly discussed for months.
My assumption is that Adam originally signed as Blockstream President, then when other members of Blockstream said that they were not on board with his plan he went back and changed his signature to individual.
Source:
https://www.reddit.com/r/Bitcoin/comments/46po4l/we_have_consensus_in_april_we_get_sw_3_months/d07h0xc?context=3IMO this is pretty serious, you cant change a contract after you sign it, and there is a big difference between his signature as an individual and that representing Blockstream.
Perhaps next time the contract should be hashed and the hash stored in some decentralized immutable ledger

This is likely the case... and if anything reflects how ridiculous the notion that Blockstream or core is a monolithic organization with a single goal, when it is represented by many individuals. Likely an oversight by Adam, and one that can be quickly rectified as other blockstream members already agreed.