why is it powerlifting?

general prescription these days for Hypertrophy is 10 sets per muscle group per week 0-3 RIR.

Mostly because functional strength is useful and keeps you alive. major goals as you age are avoiding falls and being able to continue doing things for yourself. Strength fits that bill pretty well (and it also improves fat free mass).

And on a slightly more technical note, recovering from higher volume becomes harder as you age, so focusing on a smaller number (5ish) of reps at higher weight gives you adaptation without quite as much stress.

But I should be clear, when I said real lifting, I don't mean to exclude any form of well calibrated progressive overload, whether that's strength focused or hypertrophy focused. I do mean to exclude the "go to the gym and lift a 10 lb weight the same number of reps each time" BS

Because hypertrophy is generally pointless compared to strength. The hyperthrophy that naturally accompanies strength work is sufficient but the strength that accompanies hypertrophy work is far less beneficial.

Hypertrophy and strength aren't as strongly linked as we thought. Generally for wellness, injury prevention, you want strength and flexibility.