I have a question - pet peeve

So a lot of manga have fighting, and a lot of medieval manga have warriors covered in scars.

Im sorry but for as great as they are, do these artists know basic anatomy? I was reading this one manga were the protagonist had massive scars on his biceps. But if that scar, was real, he wouldnt be able to use his arm at all, the muscle was plainly cut clean through.

I get scars are cool. I have many myself. But those wounds they had scars up? There is no bloody way they would be able to function.

It breaks the immersion.

Am I weird for this?