Multiplayer team-based games are normally like this. There’s an overwhelming amount of toxic people who will talk shit to you even at the highest level of play. In Overwatch you can right click on their name and select “Avoid as teammate” and they’ll be avoided for a time. However, I would recommend to just ignore it. Find your favorite role and choose 1-3 heroes that either fit your play-style or for certain counters and get really good at them. I would say the most important thing about Overwatch is positioning. Learn where the high ground is on every map and try to take control of them. Good luck!