For you Neanderthals versed in etiquette

I was mtn biking Devil’s Backbone in Loveland today and these rocks tried to kill me. Full face helmet for the win! I face planted and my foam armored shorts proved their value too.

When hikers pulled off the trail to let us pass, I said “Thank you, sir” and Thank you, ma’am”. My friend told me that was ageist and offensive. I don’t remember his arguments entirely so I’m not presenting his side well.

I respond like a 3rd grader when people tell me what to do so my reaction has been “you’re not the boss of me” and feel like calling everyone “ma’am” now.

But it’s entirely possible I’ve missed societal changes. Am I a Neanderthal? Should I just say “Thank you, dude” to everyone, male and female?