This phrase “I’m not being _____ but…” used in conversation (insert a word of disrespect or negativity of your choice in the line) is stupid. It’s basically an idiotic inadequate excuse to be _____.
But you are being _____! Just saying "I’m not being ______ " doesn’t make it true.
“I’m not being prejudiced but Northerners are common as muck”
gah.
Weak rant. Sorry to have wasted your time. Move along please.
No, thanks for saying that. A variant is when somebody says “I’m not trying to be difficult, but [some total piece of passive-aggresssive asshattery]”. What, you’re trying to get credit for making it look easy?
Well, I’m not being incontinent, but sometimes I’m full of crap. 
My friends do a version of this.
“I don’t mean to gossip, but…”
“I don’t like to repeat gossip, but…”
“I am not one to gossip, but…”
Yes, you do mean to gossip. You can’t wait to spread whatever you just heard all around. Just admit it, the only way you can feel important is be the one who knows everyone else’s business. You love repeating negative things about people because you think it makes you look better in comparison. And I am quite sure if you don’t think what you just heard was juicy enough, you make-up a few more details to be sure you will shock your audience.
Ooops, I didn’t mean to go off on a tangent in your thread, but…
It’s been my experience that the more someone has to insist on having a particular character trait, the less likely they are to actually have it.
“Trust me; I’m honest.” The more you insist on your honesty, the less likely I am to believe you. If you’re honest, just be honest. It’ll soon be evident. Constantly reminding me of your “honesty” just makes me think that you’ve got something to hide.
I see the OP’s scenario playing out all-too often, too. The more someone insists “I’m not _____,” the better the odds that they are in fact massively ______ (whether _____ = racist, homophobic, jealous, etc.). The minute someone tells me “I’m not _____,” I assume that they are.
I think the worst variant of this is the classic “No offence, but…”, which can be rephrased as “I don’t mean to be offensive, but…”
You get situations like “no offense, but I think you’re a paedophile.” Grr.
With respect…
“I’m not racist, but … why is it that white guys are named things like, ‘Lenny,’ but black guys are named things like ‘Carl’?” – Homer Simpson
My mum used to work with a redneck who actually said “I’m not a bigamist - I just hate boongs*”. We didn’t know whether to laugh or cry.
While I understand the point, I often use phrases like: “I don’t mean to sound like a jerk, but…” or “I’m not trying to start an argument, but…” In general, I do this because I have a sense of how the other person will respond to my point. If I really think that the person is going to misinterpret my intention, I’ll use that type of preface.
For instance, my wife was going out the other day, all dressed in white except for black shoes. They were clog-type things, with big bubble fronts. The contrast between the shoes and the clothes was so high, your eyes were just drawn to the shoes; the cut of the pants (narrow cuffs) made it look like she was wearing clown shoes. I said, “Honey, I don’t mean to be a jerk, but I think you should change your shoes.” She was slightly offended at first, but ended up agreeing with me. Unfortunately, she put on white shoes; she came home later with a request that I never let her step out of the house wearing solid white. Hey – I didn’t think it looked bad.
Point being, at least sometimes these types of phrases are used for good purpose.
Well look, I don’t mean to hold myself up as the fashion police but jeez, she probably shouldn’t even own a pair of white shoes. Taupe is your best bet for an all-white outfit at this time of year. Now, after Memorial Day . . . or if she’s playing tennis . . . well, that would be different.
As a friend once said, “I’ve got another word for people who are passive-aggressive; they’re LIARS!”
That said, I do it too. I don’t mean to rude, but… <—:smack:
Man, that’s the last time I trust the word of Homer Simpson.
Obviously. Rather, you are being constipated. 
My girlfriend told me that once, and I said “Oooh, pedophile. Big word for an eight year-old.”
It’s probably very wrong that I laughed out loud at that isn’t it…
Maybe…no one is going to accuse either of us of being fashion mavens.
At any rate, it was just the most recent example. Another might be the recurring:
“Do these pants make my butt look big?”
“Well, I don’t mean to be a jerk, but…”
I would have cried laughing myself. That’s just bewdiful.
Digital Stimulus, your hair is kinda mussed - I think you might have caught a whoosh somewhere around here 