It would give me a leverage and that would be a totally different conversation.

Though I understand that if lawyers want to destroy something they can do it regardless the CLA or anything. It's just the game of who spend more money in court.

That is answered in the article:

"CLAs shift the legal risk for copyright infringement, patent infringement or other bad acts, intentional or otherwise, from the project (the entity best positioned to defend a legal claim, and often the one most directly benefiting financially), to the contributor"

Okay. But still if a person contributes code that is not their code, even if they sign a CLA, and it ends up in the project the project can't say "not our problem they signed a CLA". The project would still need to remove the offending code.