Read the article again. Towards the end it talks about how even unpaid OSS may still be held liable.

While the US often requires consideration to establish liability even in the US in many cases it doesn't, and other legal systems operate differently.

For example, if you have a pool, even with a fence around it, you can still be held liable if a kid manages to get into the pool and drowns. It's not surprising to me that some politicians would try to stretch the meaning of liability to cover OSS too.