I have been in several situations at work, some I've been involved in others I've just been a spectator in which people have made "suggestions" but their tone and the content of their "suggestion" has automatically put others on the defensive. I would not describe the people who have gotten defensive hypersensitive. The spirit in which a suggestion/helpful hint is given often and how (time, place, context, etc) affects how the suggestion is made. We've had several meetings where people shout out changes and suggestions and nobody gets upset and everyone agrees that's a good idea. Others (typically depending on the person's previous track record) everyone bristles when one person opens their mouth and people don't even respond.
I can see little snide comments like "He's so stupid, why can't we line up like blah blah blah?" or "why do we do we have line up our horns?" made in a whining voice that erodes the patience and good manners of your section leader. Of course your section leader could be giddy with power and truly an asshole. Or he could be dealing with a bunch of recalcitrant brats. I'm not going to brand him rude and or a power trip just because your version of events says so.
I was in marching band when I was in high school and the thought was if you couldn't even get in the proper formation while practicing why would lead your section leader and drum major believe that you'll do it during a game or performance? That's what the concept of practice is all about, for you refine and demonstrate your knowledge of the music and the formations.
So I don't know how much this has to do with SJs and authority, but I do know that a lot of it has to do with how you speak and say things to people on both ends. I wanted to be in marching band when I was in high school and enjoyed it, so I did what I was told mostly. My sections leaders were made section leaders because they played better than the rest of us and typically were juniors or seniors who had been in band since they were freshman. I don't know if that's how it's arranged at your school though.