Theft of intellectual property in the case you cited also barely touches copyright. Put another way, copyright status of the property in question is largely immaterial to securing a conviction on the allegation.
Again, you’re coming off uninformed here and relying on Wikipedia (which doesn’t speak to that context) isn’t really helping.
Clean room design doesn’t protect you from patents. That’s not how patents work, simple as that.
I know how patents work. I hold 15 and I’ve defended two at trial. I’m tapping out here, since you’re simply competing with me to be less wrong the deeper this goes, and I’ve rapidly run out of patience to have intellectual property law explained to me by someone who doesn’t understand the fundamental purpose nor qualifications of copyright, and thinks it and fair use doctrine has any bearing on “I built a clone of Facebook”.
If you have the time later I’d love to hear how you can legally infringe on a patent with clean room design.