I use ads on my hobby site to pay for my hobby site. I make like $10 a year off of it.

I run ads because I'd rather not pay out of pocket but I hardly consider it as something that makes me money for the sake of making money.

When you have ads on your hobby site, do you ever stop to think about how your content affects ad traffic and revenue, or do you never ever think about the banners that you run? Genuinely curious.

Because hobbies cost money? It's not their day job, they're just looking to maybe pay for their hosting and a little more, generally.

It's irrelevant what you plan to spend the revenue on. My hobbies cost money as well, but I don't subsidize them with ads. I pay for them with my own money.

If you want to run a blog as a hobby, great. Spend your own money to buy hosting and be done with it. If you want to generate revenue off your hobby, that's fine as well, but know that it's not purely a "hobby" anymore. Even if the amounts are small or you're not profitable, it doesn't matter.

EDIT: Sibling comment may be more accurate. If you show non-profitness, (I'm speaking abstractly, not in relation to linked court decision), that would be enough to sever the link between the otherwise infringing links and your revenue.

If you can prove that you only took as much money as required for hosting (and donated the rest), a court might be fine with that.

Exactly.