We've found the same thing with other software we make. The free users and those charitable organizations and schools we give free licenses to, are the least "nice" in their technical support queries. Odd that.
People working for companies who pay are more likely to be well paid and both of (a) technically competent and (b) having empathy and some amount of charm as qualifying criteria to get that well paid gig.
It's no slam-dunk but it's more likely. People who work for organisations who don't pay are likely to be paid a little less and include some who are working a second choice gig because of some deficiencies in (a) or (b) or both. (L. is great but difficult to work with and we'll never find someone like that to hire to replace them.) As individuals they may improve their abilities in time, possibly dramatically too. The young, arrogant hotheads, sheesh. None of us were ever like that. Obviously...
The paying can be a fuzzy select for kinds of people who behave in particular ways rather than the paying itself causing particular behavior in a given person.
Make someone pay for software and they always treat you far better.
I'm sure there's some cognitive reason/explanation for this.
Remember the last time you got an item for free. You probably didn't worry too much about it, because it didn't cost you anything. You didn't treat it that carefully.
Compare that to something you bought for yourself, that you had to work hard for. You probably took a lot of care for it. You probably really paid attention to ensure it didn't break.
I feel like this is the mentality difference. Something free = no value = we can treat it badly. Something not free = it has value = we are more careful with it.
The nicest customers I have for my Saas product are also the ones who have the largest accounts. The ones that pay $15 a month for a single user on the cheapest account are always the ones asking for a list of like 50 new features to be implemented yesterday or "the product just isn't gonna work for us". Yea ok, because your $15 buys you a right to own my entire roadmap... not.
They’re paying for whatever product or service they went in for. It’s not because something is free, it’s because they’ve designated certain people as servants.
I think there’s a pernicious attitude that the “free” part of open source is an entitlement to service, and that the people providing it are servants.
I think products do have the ability to make us feel an emotional response, even when free?
Apart from gifts, as mentioned by another commenter, I often seem to value things higher and be more careful with them when I know they're valuable and I got them without having to pay.
An example would be when I, through a misunderstanding, received two copies of a $16 promotional Magic card for free from my local game store. I tried explaining that they gave me something way more valuable than the free 30 card deck I had a code for. They just threw in that free deck as well and didn't want to hear it. The cards have since decreased in value somewhat, and I have other much more valuable cards, but the story of how I acquired them somehow make those cards feel very valuable to me.
Do you pay for the oxygen you breathe?
So if people made a monetary investment they have the emotional need to justify to themselves and others that they made a good decision (hence you talk positively about that purchase), however somehow when they use something free, people don't feel that emotional need.
Indirect correlation if you ask me.
"Consumer" users are most likely to behave as consumers, ie not being interested with the project but their work getting done. Open source distribution channels are often independent from the actual project management, opening the possibility for varying degrees of quality.
Paid for bugs are more irritating than free bugs. Consumer support is rare for "paid for" software (good luck getting support from Apple radar, google services, iOS App Store ...) where open source projects provide forums, issue trackers ...