To true. I read it as the OP was talking about being a jerk, not targeting competitive play. There are jerks on every side of this game, from fluffy players which snobbishly deride you if the number of purity seals on Tactical Marine #II-5 is wrong, to people who don't realize you're a new hobbyist and say, "you should thin your paints" without explaining what they meant, and casuals who blow by rules just to make the game run quicker while ignoring important steps or gossip-snipe you behind your back.
But let's face it, the first place we go when we think about jerks are those competitive types, just as when we think about sleazy people we think used car salesmen or politicians. Why? Because it is easier to catch them at it? Because when we think competitive, we think of those jocks who gave people swirlies in grade school? Or is it just because it is harder to identify the fluff-jerk or the casual-jerk?
In one case on the original post, the guy didn't know he was going to be a jerk because he hadn't thought things through to see it from the other person's perspective. As soon as someone pointed it out, he thought about it, he changed his mind and stopped himself from being the accidental-jerk.
Key point, just be aware of others and try to avoid being a jerk.