why is it that children tend to type in this particular manner?

XxxyasuoxnarutoxsasukexxX : suckkkkk ur momsssss dickkkk %%%ggg

I.E with all the unnecessary letters at the end of the word? it's always been consistent with the ones that exhibit other childish behaviours (not general toxicity, just childish behaviour, I.E; asking to 1v1 to prove skill in a team game, or things along the lines of that) why do you think this is? when children get toxic, they always seem to type like this? has anybody else notices this?