This is good advice, and this is exactly how it is. Don't expect compassion from people because you stutter, it may feel unfair sometimes but I've learned that the world isn't always kind and doesn't always take into account the fact that you're different as a stutterer, because you are, there's no way around that and you're gonna have to cope with that one way or another. But you have to do it yourself. Indeed you need to develop a thick skin for that, and the best way to do that is by constantly exposing yourself to your fears and situations where you're not comfortable, and you'll find that it really does get easier, as it will take away the fear. I'm convinced that the biggest problem is fear, and not exactly the stuttering itself, it's there and it is a problem obviously, but the fear is something else and the fear is the root for a lot more problems (also mental health) than stuttering itself. The fact that you were fired.. well people can be harsh, like I said the world isn't always compassionate, people get fired all the time for stupid reasons, and if you think about it, it's not anyone's job to be compassionate. But don't worry, you'll definitely find a workplace where you can be who you are, no doubt.