Choice? Options? These people were going to leave kernel dev anyway, now we get to see them try something new. Maybe it'll work, maybe not, but what's the harm in trying?
The way I read it was thus:
Dev - this Idea sounds pretty rad, here is some code, merge it into the mainline kernel.
Linus - this doesn't fit with the direction I see the kernel going in
Then dev tries to force his opinions on the group, Linus blows him off with hostile language, then
Then come the big DUMBASS moment, the Dev, instead of saying "OK I will build a branch like the mm-kernel branch ETC" and then shows how his code both works with the kernel without breaking stuff and proves that there are real world advantages to his inclusions, but instead screams out " you all are big meanies", then essentially steals a clone of Linus' ball, goes and sets up a "fork" that is completely separated from the mainline kernel devs and feels smug "because he knows better than Linus" what the kernel needs.
Hell, even providing a branch with his contributions on github without all the histrionics would be fine, but that wouldn't get nearly as much attention as whining about Linus " being a big meanie with BSD hatred / envy".