Why are some professors and instructors like that

Why are some professors and instructors like that I study at a university and my program is connected with languages, speaking and communication. I can’t say I was always looked down on, but I felt that some professors and instructors treat me differently just because I stutter. I’ve never asked for additional time when doing conference reports or presentations, I’ve never asked for special treatment. I always try to convey my thoughts smoothly and use the words I less stutter with. Though sometimes I just can’t fight my nervousness. I study Chinese at university as well, and we had a certain professor that seemingly didn’t like me just because I stutter. We had an unrelated conflict going on, and during that she said something along the lines of “I have a friend who stutters, he is working as a translator. You don’t have to speak, you can just translate books” when the topic wasn’t even about stuttering. I didn’t ask her for any guidance or advice. And it really made me feel awful because why is she telling me that? That’s not really empathetic to me, even if she had good intentions. We had a conference report with the other lecturer, working in a team of students. She was assigning presentation slides to each one of us and she said that I only get one slide, even though everyone would get two slides. I didn’t say anything, but I felt like she was ashamed of me. That conference is important, and I didn’t argued that I wanted two slides (like everyone else got), because if it’s important for her that I don’t speak much, let it be so. But I felt really sad. Then she accentuated that we only had two minutes to talk about each slide and I should keep it short. Does she think I don’t know? Of course I do. Of course there are professors and instructors who are kind to me, and who encourage me to participate in conferences and all. But I wonder if it’s always going to be like that with other professors just not seeing my competence and strengths because I stutter. I’d like to hear your stories if anybody encountered the same thing. Thank you