Because these labels are made out of plastic instead of paper or paper-plastic combination. Plastic is not only more expensive, but also worse for the world, hence most labels are made of paper and rip in two when trying to peel them off.
It also depends on the adhesive and climate. Eg. Post-its and masking tape rarely tear or leave a residue when removed from a smooth surface that hasn't been in an overly dry or warm environment
For non-consumable stuff that's really great. For food items I don't want a resealable sticker. There's a benefit to being tamper evident in those cases. It'd be nice if they were easy-peel and not restickable. That'd be dope!