No it's not normal.
Sure, some people will be dumb and do that.
But there is no reasons to antagonize someone who didn't do anything wrong to you, was helpful and will surely be even more helpful later...
People who does that are a minority.
Lets see. If such people are minority, then why are such situations are always in the media, be it books, movies, comics and mangas, video games and folk stories, sayings like “nail that stick out gets hammered down” and so forth? Does it mean everyone is just up for the drama through out the history?
Also, your naïvete in your comment tells me that you personally never experienced raise to the prominence (read; being recognizable force in your field). Or it is just pure ignorance. Or playing blue troll in a dress.
But regardless. I don’t mean that such arsehole behaviour is normal and everyone should strive to become one drunk on power (like some politicians and richest people out there). Such actions are pure corruption and lead to the dark side, but rarely prosecuted, unfortunately. It is just a normal everyday fact that majority of people of power are corrupted one or another way, and portraying such people in manga antagonizing characters that potentially threat their source of power and status is quite mundane occurrence. If anything, I am disappointing this trope was used at all. Not because they are bad people doing bad stuff to our beloved protagonist and his friends, but simply because we all know that it is a lazy vessel for a character growth and plotted armor of overcoming struggles “the right way”.