why are jealous people such a pain in the ass

my question is. why are people so jealous of me? I'm not trying to brag about it or make it like a flex but it's actually a real pain in the ass. for me I actually really do not get people who are jealous of someone, I mean They aren't hurting you you are the one who is bothered unless they did something bad to you but that isn't what I'm discussing right now, I'm talking about the people who get jealous of a person who doesn't hurt/harm them, I mean what kind of mindset are you on, I have encountered numerous type of girls who have been my friends and they are the best girlfriends I ever had, but I also encountered a lot of girls who gets jealous of me for absolutely no reason and I don't know why, a few months ago when I was at school,  I was just casually living my day when all of a sudden a girl I DIDNT KNOW a.k.a a stranger was trying to copy my style, I was wearing a really cute sweater and cargo pants and she was wearing the same thing, I'm not trying to assume shes copying me but just listen to my whole story, but when i saw her early morning she was wearing a different outfit, she was wearing a jacket and shorts. At first, I thought it was a coincidence so I didn't really think too much of it, fast forward I think a week later after that incident while I was scrolling on TikTok, my best friend Julienne told me that the SAME girl who copied my outfit was COPYING my content on TikTok, I thought that Julienne was just assuming it but HOLY COW she was copying my content, the number of videos I saw of her copying my content I think it was like 12 VIDEOS, and after watching all of the TikTok I started to realize that she is copying me, I thought I was just thinking about unnecessary things, and I was like girl where is your ORIGINALITY, what's your point of copying my content, first you copied my outfit and now you stole my content?! I was so ready to confront her on Monday, but Julls was telling me 'It's okay Ellie calm down do not worry' so I tried to calm down, she also said that she would ask her friends if they knew this girl because she had a lot of friends. when it was Monday she called me over to sit next to her at lunch because she had to spill the tea, she told me that the girl's name was Macy and that according to her friends, she was JEALOUS of me because I was friends with her crush, Chris, he was my childhood friend and I never had any interest on him, he already knew the guy I liked, and when she was telling me about this I didn't notice that Macy was there INFRONT of us and she was glaring at me, I immediately stopped Julls and I whispered to her 'Julienne shes right in front of us'. At that point me and Julienne FROZE because Macy was starting to walk towards us, she told us 'Hey I know you both are talking about me and no offense you both look ugly as hell, EXCUSE ME!? says the girl who copies my every move, at that point, Julienne was about to throw hands at Macy when the people from higher grades stopped the commotion, and Macy was acting like she was the victim and blamed at us that we were bullying her, after that incident Macy is still jealous of me, yesterday she changed her whole personality that was similar to my personality, she changed her style to mine, and she was also trying to be in MY friend group and she tried to steal my friends, and I don't know what to do with her, she stole 1 of my friends and I have been worried that she might steal the majority of my friends one day, AND I DONT KNOW WHAT TO DOOOO ;[

- this is why the people with the same mindset as Macy are actually crazy like why so jealous bro, (this is just my rant so don't judge me)