I understand that having others tell you what to do with your speech can seem condescending. It's uninvited and, because you didn't ask for the advice/help, it comes as a surprise. But, I stand by the owner. That's because if you do calm down and slow down your speaking, your speech will improve. I know this from personal experience. The faster you speak, the less in control you are of your speaking. You'll have better control when you make yourself speak slowly and it's done in sync with deep breathing (speaking on the exhale instead of the inhale). We've all been defensive in situations like this. But take his advice as a gentle reminder. Let them know that you understand what they're saying but, honestly, it's the best advice. Find ways to stay calm and slowly say a few words at a time. From my understanding, he's doing this to help you. I also mention a few other things in this video: https://www.youtube.com/watch?v=-Fw3h1-c2io