Linguacidal tendencies

I'm not actually sure what the correct word is for the murder of language, but linguacide seems apt enough. Today I saw written on the back of a car's windshield, in soap (or whatever), "your the shit", and I wanted to scream at whoever wrote it that they are, in fact, retards. Or, "You're retarded". I mean, seriously? How damn hard is it to know that "your" is possessive, and "you're"=="you are", as in, you are retarded, and it's all your fault. I remember the yours, along with all the toos being taught since grade school. Every single english class for years would point out the difference between these commonly misused words. I feel like pulling a Lewis Black and shouting obscenities at the utter stupidity of people. Granted, I still have problems using affect and effect, but I'm trying to learn, and those are far less frequently used, and thus are less worthy of berating for the misuse. Gah!