Often it's because getting involved on the business side means doing a lot of politics. Is this problem more urgent than that problem? Who will take credit for solving this problem? If I solve this problem, will they fire half the people who currently solve it manually? If I solve that problem, will it empower a certain scumbag VP who's been clamouring for it? Etc etc.
Codemonkey doesn't want to be involved with all that shit.
I don't think GP means getting involved with business side decisions, just understanding the "business logic". Where "business logic" is a generic term for anything, it could also be the rules of a sport, how the competition(s) are structured etc. if you are building a sports website...
Requirements engineering can be extremely draining regardless of it.
What's that? We're three years into this six months project and you just realized again that you don't understand your own job, don't understand the legal requirements placed on you, nor your position in the overall organizational architecture? Of course we can rewrite everything from scratch for you, again. What do you mean there's no budget and it has to just work?
Codemonkey doesn't want to be involved with all that shit.