Film doesn't age well

"The message I got is that you should rebel against authority because they're a bunch of ignorant old fogies who want to extinguish your inner fire."

You got the wrong message, IMHO. I think the message was more about digging deep, finding and embracing passions in life. The rebellion aspect seems to only make sense if you're against everything your elders are for. Granted, the school was pretty lifeless and dull but if your circumstances have that much of a hold over you then you're likely not going to be passionate anyway.

The OP seem to forget that the "rebellion" didn't work out so well for a few of the boys most influenced. Keating's influence on Todd (Ethan Hawke) was probably the most beneficial, encouraging him to crawl out of his prison of hesitation and explore the "inner fire" he never thought he had in him. This was probably life changing for the positive for him, although his choice of college might have been derailed from his unwillingness to sell Keating down the river. But look what happened to Neil. He wasn't prepared to deal with his father's disappointment and ultimately killed himself. Charlie got expelled for his Keating inspired antics, and many other kids probably wound up with some scar or other on their transcripts. The filmmakers chose to include these consequences of youthful rebellion in their story. It seems clear to me that they were warning about precisely what the OP seems to think didn't happen in this movie. Namely, that a youthful, careless rebellion against authority (from kids even more sheltered than Keating) can have dire consequences. Why the OP chose to ignore this obvious theme to the ending is a mystery.

Growing up as a working class kid I never understood the suicide over acting classes. That just blew me away. Given the problems I was working through the idea of someone shooting themselves because Daddy won't let them play pretend was just astounding to me.

I did love the poetry group though.

I don't know but it sounds like you ended up agreeing with Neil's father?

Keating inspired the young boys to see outside the rigid box of educational requirements and to appreciate the arts and what inspired them into existence. I had college professors who were utterly perfunctory and dull and I had others who inspired me to hone in on my passions.

It reminds me of when I go to my middle-aged, single sister-in-law's house and see the trite inspirational quotes she has framed on all the walls (even in the bathroom). It's corny and naive, and desperate for approval.