> Language has rules (They were taught to us in school). They might change over time but they still exist.
Those rules are discovered, not handed down from authorities, and the rules you were taught in school are largely not the real rules English speakers abide by. The real rules are learned the way every native language is learned: Through imitation and conversation with other native speakers, the caretakers and the peers.
> Iz their know point at witch "human caltoural fenonemon" stops and blatant misuse starts? Would you not draw the line somewhere?
First, we're talking about language, not orthography. If you want to see some bizarre orthography, read Chaucer. Or Shakespeare. Or Lewis and Clark, who managed to spell "mosquito" multiple ways on the same page, in full view of each other.
Second, native speakers do make mistakes, but if a "mistake" is persistent enough to bother you, well, it probably isn't a mistake, but a dialectical feature, and saying a dialect is wrong or inferior is contrary to the science of linguistics. You wouldn't claim to have a new rule for electrons and then rant about how the electrons refuse to follow it because they're uncultured and uneducated.
And saying a dialect is "wrong" is very often a proxy for saying some people are too poor or the wrong color to "speak right" in the mind of the complainer. Witness the idiocy spewed about African-American Vernacular English, commonly called "Ebonics" by the people who try to mark it as uneducated.