Friends Don't Let Friends Proselytize...

Actually, I don't consider what I do as proselytizing, but many people react as if I'm trying to tell them I'm right and they're wrong. Maybe subtlety is my problem.
Anyway, I've received threats from someone I went to grade school and high school with on a social networking site. I told one person I didn't like the phrase "short bus" to be used as a derogative remark. He got annoyed at my wording and snipped back at me, then I apologized. Then he apologized. Misunderstanding aside, we put it past us.
Then "coincidentally" (or so I was told), another "friend" wrote a vicious diatribe about how he hates overly sensitive people bitching about their "tard" kids. Why don't we just get over it, he asked, amid scathing remarks about these parents and his ignorant understanding of "waterheads". I assume he means babies who were born with "water on the brain" which resulted in mental retardation (by the way the new DSM completely got rid of the mental retardation diagnosis; it is going to be intellectual disability now).
Of course, that isn't the sole cause of mental retardation. He also pointed out that idiot was a clinical name for MR. Back in the day it was, along with imbecile and moron, it denoted a level of MR severity. Those words became degrading and stigmatizing, so MR was introduced. How long before the new label is common derogative slang? I will admit that intellectual disability doesn't quite have the ring that idiot or moron has; maybe we can keep picking longer phrases with less "appeal" to the lowest common denominators in society that choose to slur others with these words.
This one person isn't the inspiration for this post; far from it. He merely exemplifies the arrogant ignorance that is pervasive in this society. He probably says fag and n*gger to insult people as well. After all, according to him, "I ALWAYS win"... (ah, the mantra of the enlightened!)
Years and years of stares, pointing, and name calling have led me to my near-proselytization of friends, family, and acquaintances. Most people are nice enough to apologize or at least change the subject. The less polite go off on a tirade about how I can't tell them what to say, and "That's not what I meant anyway! I'm not making fun of people with disabilities!" I suppose the fact that making a diagnosed condition's name synonymous with stupid, dumb, ignorant, and gullible is inherently insulting is lost on these individuals.
Let's say you have diabetes. How about I assume that since you have diabetes you must be overweight, not exercise, and are lazy. Then I begin to call anyone who is lazy or overweight "diabetic". Would you take offense at the idea that I categorize all overweight and lazy people as diabetic?
How about if I assume that because you have are a single mother with a low income that you are a mooch, having kids just to get welfare and food stamps? "But I'm going to college," you protest. Well, I just think you're doing that to borrow student loans and keep the welfare coming. You're lazy and I know you'll never make anything of yourself. You're just wasting tax payer resources that people like me pay for.
I would sound like an arrogant bigot with her head up her own *ss, wouldn't I? If you think so, then maybe you see my point about using retard being offensive and demeaning. If not, you're probably a bigot.
There's hope for reforming bigots; they are generally bred out of ignorance and fear. I was quite the prejudiced, bigoted *ssh*le growing up. It took me several years to get all of the stupid prejudices I'd learned out of my head. So I'm not trying to be a holier-than-thou proselytizer. I'm just sharing my opinion.