Groceries regularly do price discrimination (and have for a long time) via coupons. People mostly seem to be fine with it.
Uber's price discrimination is opaque. Even if they aren't doing dastardly things with it, people don't like feeling ripped off. We have no way of knowing when we are.
1. The existence and mechanism of coupon programs is visible instead of secret.
2. They are not based on creepy individualized spy dossiers.
But most big box stores have moved to digital coupons that are indeed customized based on their creepy individualized spy dossier on you. At our grocery store, my partner and I get different coupons or even different deals for the same items.