ISTPs are the type that won't start that many fights on their own, but usually have no problem joining in if their friends get into one or get attacked (maybe more so with physical fights, than verbal ones). While IxFPs might be more likely to just not do anything.
Most I know like sports and competition and getting scrappy. But just don't start that much shit.
I agree, I dont like conflict, but I have asked my wife many times "you want me to do something about it?" When I do respond, I try to do it quick, and get it over with and move on like nothing happened. Have never been in a fight, dont have any enemies, no one really ever messes with me in a negative fashion. Never understood this.
edit: they do mess with me negatively sometimes, but it always seems to end pretty quick.
Take what I say with a grain of salt, because that's all it is compared to the ocean of complexity when it comes to actions and real life.
My ISTP bf is definitely not afraid of trouble... when he was 12 or so, he was joking around with a spray bottle in the classroom when his xSTJ teacher tried to break the crowd up to start class... well, ISTP bf just squarely sprayed the man in the face with water! For shits and giggles. After that, and maybe a couple more skirmishes with each other, the teacher resigned.
It's not that he likes to start conflicts, but he does like to stir things up for fun--it's just that his brand of fun is often at odds with others, particularly the go-by-the-rules types.