Earlier quoted context omitted.
I have this junior engineer DM'ing me right now and I've been ignoring it because I don't want to deal with him and I have my own work to do. I'm reading through your comment here thinking "hey, I'm pretty good at walking that line, bothering the professor when appropriate, not waiting too long and not asking him for help too soon"... and then it occurred to me this guy is probably bothering the professor where I'm t…
If your a senior dev it’s part of your role to help the junior ones out. You should cultivate that behaviour as it brings up the quality of your colleagues and builds work relationships.
Then, when you graduate and can start making real money (probably), if you work at a hospital that does resident education, you're almost immediately expected to let the residents do as much as they can safely do, so they can learn. You go from working 80 hours a week performing surgery after surgery at a senior resident to working 30 hours a week watching the senior resident perform surgery.
Similarly (and admittedly it isn't a perfect analogy) as a junior and mid-level you're spending all this time learning how to write real software. Most of it's bad and especially at the junior level you're going to spend a couple years being more trouble than you're worth in terms of productivity. But by the time you're a senior, when you theoretically know what you're doing, you're going to have to spend most or a large portion of your time helping out the juniors in your org.
If you don't want to do that, you shouldn't be accepting senior positions. Or at least, go work somewhere where they don't hire juniors.