The entire point of the CRA is to make "manufacturers" liable for the quality of the software they produce, in a similar manner to how car manufactures were held liable for the Takata air bags. But who is the manufacturer. In the Takata case it was the car manufacturers the car owners held liable. This LWN comment spells how how difficult it is for software: https://lwn.net/Articles/956218/
One sentence from that highlights hints at the problem:
> the CRA's explicit statement that things qualify whether or they are provided gratis.
The CRA as it stands doesn't draw the line in a way that clearly exempts a bunch of high schoolers uploading their code to github, possibly because no one has figured out how to do it in a way that doesn't also give Google Chrome & Android a free pass.
To put it another way, you've asked an impossible question. You can't point to the faulty clause that exempts open source, because it doesn't exist.