It sounds like he’s just a dev who’s in over his head but either doesn’t want anyone to take his baby or doesn’t want people to see his sloppy and possibly insecure code

I’d bet it’s a LOT more along the lines of the second guess, because it’s now cost his wife her job and has gotten him quite publicly tagged along with it. He’s got a large portion of himself invested in it, and of course it will sting and suck for a bunch of folks to come along and point out, both gently and horribly, knowing OSS folks, all the shortcomings and then make changes.