Scott is basically the werewolf equivalent of the product of an extremely misguided drunken one-night stand.
Because turned werewolves are Alphababies, right? And Scott was a bite-and-run product of a full-moon-high newly-made Alpha. Only moongoggles (werewolf equivalent of drunkgoggles) could make Scott seem like a fantastic choice.
…so Scott is both the extremely drunken one-night stand AND the illegitimate werewolf baby that everyone’s like ‘wtf do we do with it now?’
Which is why Derek has the same face pulling Scott out of trouble that the Sheriff does pulling Stiles and Scott out of trouble. It’s the ‘why God why’ look, and I LOVE IT. Clearly Derek thought Scott was an anomaly. That other teenagers would be smarter. Which is true, everyone is smarter than Scott (I do love him, but he is not bright), but that does not mean the other teenagers make better choices. It just means they don’t use Allison for a username and a password.