Open source is a good example of people not acting for immediate monetary gain, you're right, although legally the licenses rely on copyright law.
I absolutely didn't mean to say the comment I replied to was necessarily wrong, I wanted to point out the commentator made a confident claim that completely failed to address any of it's well-known counterarguments. I meant to criticize the commentator for failing to acknowledge that reasonable people have argued against their case; if I had used that to make a case that their argument was wrong I'd have succumbed to the ad-hominem fallacy.
