What exactly is it about external frame packs that sends the modern ultralight plastic subaru consoom product cityfag into such uncontrollable fits of seething and rage?

I'll go ahead and admit I've never tried any "modern" internal frame pack (e.g. from Osprey etc.) because I don't see the fucking point. Why would I want my pack to NOT ventilate my entire back? Why would I want my pack to NOT have a frame that can be detached and used elsewhere? Why would I NOT want my pack to be adjustable to the frame, instead of being forced to buy a pack "sized" for me? Why would I NOT want a overhead frame to (very comfortably) hang my arms off of while walking?

There is but one semi-legitimate criticism of external frame packs, which is that they aren't good for bushwhacking as the frame can catch on brush. This isn't even valid for 90%+ of backpackers, who stay on established trails and/or hike in open country. And if you're worried about 3 pounds of extra weight, give up added sugar for a week and there's your precious poundage.

You were forcefed internal frames because they are cheaper for the modern consumers, and because they have some degree of planned obsolescence due to not being adjustable. Me, I'll keep my old Kelty that I've had since scouts (and have, by the way, adjusted larger as the years go by).