-Gavin is the only dev who supports this proposal
Gavin's method of slowly raising block limit is simple and it works. The other proposed sidechain method is complicated and premature. He is out numbered not because his direction is wrong, it's because the other devs have "personal interests" on their solution.
-Gavin was planning to foist his and Hearns' XT altcoin on the community for one year plus and this was all planned for a long time.
The others devs' founded Blockstream, it was all planned for a long time too. It has been receiving millions of funding from "investors". Are these devs likely to push their sidechain tech or follow Gavin's method?
-Gavin caused a decline in the price of Bitcoin which could possibly turn into panic selling (we don't know yet)
-Gavin caused a serious loss in investors confidence and thus harmed Bitcoin greatly
Gavin did not cause the difference in opinion among the devs. All the devs as a group caused it. Besides, panic selling and loss in investors confidence is speculation.