I think you're missing the point - I meant to imply that, according to the RAW, it isn't possible for a rude, abrasive, jerk to have a high charisma as the two concepts are mutually exclusive (well, as the RAW defines Charisma, anyhow).
I disagree. The concept of charismatic jerks is *very* ingrained, not just in D&D and fantasy, but in Reality. Some of the most charismatic people I know -- the most perusasive, the most compelling, the most likely to be the person you talk to in a crowded party -- are also the most incendiary, contradictory, narrowminded, rude, abrasive jerks in the world.
But despite that...or BECAUSE of it...they grab the attention in the room. Not nessecarily for the positive, but EVERYONE will haven an opinion of them (and most will agree with the rude, abrasive jerk). "Girls only like jerks" and "Guys are attracted to heinous wenches" are folk-wisdom evidence of this tendancy. It's not universal, but it is widespread. Think of how the rich and powerful snobs of the world treat those "lower" on the scale...think of how demanding some actors can be of simple service staff, think of how much of a completely unpleasant person some music stars are (Rap stars in particular in the modern-day, but the cliche hair band of the '80s bears this out, too).
These people are CHARISMATIC, they have a strong personality and get people to do what they want, but they are not always pleasant people. It just takes a high Wisdom to see through their charisma and notice what pure jerks their being -- a wisdom that most people don't have, a wisdom in excess of their charisma.
The charismatic can be egotistical jerks -- indeed, in some conceptualizations, they *tend* to be egotistical jerks.