Its called lack of thinking for the most part - I might not classify it as stupid (although to me it is as it seems so obvious) - I think it is more that "duh" moment - they did not think it through or are very young (at least in mind) and lack experience in a professional environment.
So say for instance you are applying for your first job. You never have applied for a job before and you have little guidance - you open the application and fill in the required information and then it asks for your email and you put in [email protected]
never thinking about it as you have used this email since you were 12. Forgetting that the nick name is not very complementary when you originally set it up and basically not thinking about it - just typing it in.
Should it be obvious? Yes. But think back when you were 16, 17, maybe even 20s - you probably did something equally dumb - but if you thought about it first you would have caught yourself.
Having two young adult daughters now - this is what they experienced so when my daughter was first considering colleges, both for academics and for athletics - her AAU program gave guidance on how to go about doing searches for potential colleges and how to reach out to coaches, as well as her high school guidance department did similar for academics. They both made it clear to have an email address set up that was professional sounding; without any nicknames or anything else. (i.e. [email protected]
). This is directly as a result of what you are stating - you don't want a potential coach or school admissions to think you are a dickhead.
It seems crazy but they are now teaching students on how and what kind of email name you should choose. Hopefully you will see less of these dumb emails as a result.