Makes total sense. You're unlikely to use Linux if you're not something of a power user, at least. I would guess there's a lot more developer type people who use Linux, and they are the people who appreciate a good bug report.
Same people also have a better idea of what might be causing the bug, how to get more information, logs, and so on.
They're also probably more used to the development process. With proprietary software, if you don't pay for a support contract, you basically can't submit a bug report - not really. You just ignore the bug and hope it's fixed in later versions.
This applies to big AAA games too, so games aren't necessarily special.
But indie games are in a weird spot where:
1. They're clearly artists. Nobody who want to make tons of cash becomes an indie game developer. If you have the aptitude to grind through the docs and make a game, you have the aptitude to grind leetcode and get a comfortable job somewhere that pays benefits and cash. And since they're artists, and they're making games, people empathize deeply with them.
2. They get a bit of a pass on the whole free software zealotry thing. I'm sure some people are still hard-line about it, but like, if I had to rank software in terms of freedom-threat-if-proprietary, something like Office or a compiler and towards the top, and Valheim is rather closer to the bottom.
3. They really have to listen to their players to survive, so they end up operating a lot more in the open.
So they end up looking a lot more like an Open/Free project than you would expect.
I think the title was intentionally a little clickbaity but I'm not exactly bothered by it. Clickbaity is a negative when the bait-and-switch robs you of the pay-off. In this case, I think it was overall a more interesting story and so for me subverting my expectations was actually a pleasant experience.
Reminds me of a tweet from Yann LeCun a while back where he bragged that they take down more reported content than other social sites. While at the face of it, this seems good, what it really means is that their system is worse at proactively taking stuff down before it gets reported. If they took everything down that violated their terms of service before it was noticed by someone else, they'd have a 0% follow through on these take down requests.