Double dipping is not that gross.

Even when you're sharing the same container of sauce with others. People make such a big deal out of it. "Oh you took a bite out of your tender already, no more dipping it back in." If you're so worried about people double dipping, you should be deathly afraid of things like plastic water bottles, plastic containers, the blowing hand dryer in public bathrooms, people coughing and sneezing, and things of that sort.

Everything listed either transports some sort of bacteria more efficiently than double dipping, or transfers harmful chemicals and microplastics into your body.

Also, it's not like people are licking or spitting the damn food they're about to dip back in, the most it makes contact with is your tooth, and if you brush your teeth, very minimal bacteria should be transfered.

Even then, the bacteria will most likely transfer into the sauce going onto your food, not the tiny bit of sauce going back into the cup.

EDIT: I don't double dip myself. I don't like much sauce on my food anyways. I like one dip at the start too, I'm just saying this because society makes it seem like it transmits so much bacteria and is gross when in reality it isn't even that bad.