I'm some ways, I get your analogy, but I think you're making an assumption that it doesn't support.

Open source software is rarely "here's a free chair, that also doesn't have splinters." It's far more often "Here are some free blanks for a chair I made. It's not totally finished, so you'll probably need to do some work on it yourself. But the joints are easy to dis/re-assemble, so feel free to examine it all and modify or replace them to meet your needs. Also, don't sue me."

In that context, it's much more understandable, not because anyone's wrong per se, but because fundamentally the expectations are mismatched.