Why do best/close/good friends get into terrible fights? My best friend refuses to speak to me and it’s been three months!

I hate when friends fight. It breaks my heart. I’ve gotten into fights with my friends. My best friend is currently not speaking to me because she thinks I’m supporting people that kill animals to make fashion coats. I wanted to join the fashion show. She was excited for me until she looked at the fur coats. She suggested I shouldn’t sign up. I didn’t wanna miss a chance to be on the fashion show so I did with the permission from my dad. My beat friend went ballistic! She screamed, “Layla (me) HOW COULD YOU?!!” I apologized but I couldn’t miss out and it wasn’t her place to tell me what to do. She yelled at me that that is cruelty to animals and I shouldn’t do the show. I asked her to stop yelling at me but she said, “Well I’m going to because you chose to do the show and you didn’t even think about MY FEELINGS!!!!!!! WHY?!” She’s a vegetarian and been one for two years. She’s annoying. We got into a HUGE fight and she screamed, “I can’t support you! I DONT WANNA BE FRIENDS WITH SOMEONE THAT SUPPORTS ANIMAL CRUELTY!!!! That is WRONG!!!!!!!!!” She stormed of and started crying. It’s been a while and she still won’t talk to me. The fashion thing got cancelled due to COVID 19. She hasn’t spoken to me since April. She won’t text or call me back. What is her deal? I am not cruel to animals. Why is my friend acting like this?