Obviously, there's a flaw in that logic. A CLA is an agreement between a project and a (new) contributor. A project does not absolutely requires the contributor to sign the agreement to accept its contributions, in theory. It's the reverse: for the contributor to have their patch accepted, they need to accept the CLA. But the project could accept contributions without CLA without violating the law.

But it seems that projects sometimes end up doing a DOS on themselves by refusing perfectly fine contributions from drive-by contributors who don't have time to waste filling forms on all projects they stumble upon.

In the case of this typo, I could have submitted a patch, but because I didn't sign a CLA, again, the project couldn't have merged it without breaking their own rules, even if someone else submits the same patch, after agreeing to the CLA. So, in effect, I would have DOS'd the project by providing the patch, so I just opened an issue which strangely — and hopefully — isn't covered by the CLA.