What is it with the mentality of high ranking and normals

I don't exactly understand what goes through peoples heads. A little background, the account I'm currently using is Plat 2 and a strictly solo lane main, particularly Jax top. I've been playing normals recently and playing as adc to get familiar with it so I can shift over to it if I feel like it. Anyway I almost always get flamed for doing bad. This isn't the part that annoys me it's the remarks such as "boosted account", "boosted shit", "how much did you pay for your account" etc etc. Like seriously I'm playing normals to have fun and learn new things not play my damn best every single game. And this isn't an on and off thing either it's 90% of the time I go negative. Even with a score like 1/3 I'll get flamed for being boosted.