Why was I denied from receiving Disability if stuttering specifically is listed in the ADA

Why was I denied from receiving Disability if stuttering specifically is listed in the ADA Stuttering is listed as a disability in the Americans with Disabilities act. I went through the whole process of applying for disability. I had to go to an evaluation with someone who monitored how I spoke. I got stuck on almost every word(like usual), and took upwards of 5 minutes to say a single sentence(also usual for me). I was quickly denied from receiving any disability payments. I went to a disability lawyer and they said I had no case because I am perfectly capable of working. How does this make any sense? How is stuttering classified as a disability but doesnt qualify for disability?