Should devs be held accountable
No. As long as it opensource software - no, they not. If you like idea and have some free time you can improve coin by yourself, this is how open source software supposed to be developed. If devs not sold something on "ICO" they can do whatever they want.
If it is opensource and not an ICO (and not a Dash-like obfuscation of a commercial enterprise), then there is no one set of developers. Anyone can hack on it. Token holders could fork if they want.
So yeah in that case devs don't have any obligation.
But maybe some devs have good reputations, then it probably will help confidence in that open source repo.
I am not anonymous. I am a dev.
W.r.t. to ICOs,
they are illegal, so I have no interest in them.