Sajak has made a living with humor that makes fun of others since his days on the Armed Forces Radio Morning Show in Vietnam. It is his "schtick." But, there is a difference between an offhand comment about someone's hairdo or shirt, and mocking a physical handicap. How would you feel if he told a kid in a wheelchair to hop up onstage? There are limits.
My ex-wife was the Senior Contestant Coordinator for one of the most popular game shows of all time, which featured one of the best hosts ever. He never made a negative comment about anyone on the air. Nobody had to tell him that other people have feelings, too.
Game Show Contestants are "us" only braver, sometimes smarter, and with bigger dreams. Most of the ones I have met over the years can really use the money they are trying to win. A contestant with a speech impediment has overcome a lot, just to try out for a show. Mustering the courage to go on national TV, makes them special. Having the host ridicule them, takes away all of that special "shine." Every person who has a speech impediment who saw themself in that contestant was trivialized by Sajak at the same time. And, it is not an important part of the show. It is just something Sajak does that is wrong. There is nothing right or good or special about a big star using their status and access to our homes to belittle someone who has no control over how they were born. I am sorry for you if you think that is OK.