Other people don't know, and they make bad choices in the moment. They don't know what they ought to do when someone is stuttering in front of them, they're aware they don't know what to do, and they feel awkward. So, they do unhelpful things, often thinking they might be helpful. They look away, they interrupt you to finish your sentence, they tell you to breathe. They might even nervously giggle. This might be a totally new and unfamiliar experience to them, even though you live with it daily. Someone who is struggling to suppress their stutter makes it even more difficult, because there is often visible tension and unusual secondary behaviors that can make a stranger feel even more uncomfortable. The answer isn't easy, and it takes practice. You force yourself to become comfortable allowing people to hear you openly stutter. Practice with strangers, practice on the phone, focus on your own reactions because that's within your control. Any stutter no matter how intense is still better than being isolated because you're ashamed to speak to people. Some stuttering isn't so awkward if you don't let it be awkward. You'll still occasionally encounter unempathetic people who mistreat you, but that has to do with them and not you or your stutter, and honestly if you didn't stutter they'd still be a bad person and they'd probably mistreat you for some other reason.