The closed source or patented stuff can't be used regardless if someone is part of the open source community. No one gets sued for using the open-source stuff,

The closed source or patented stuff can't be used regardless if someone is part of the open source community. No one gets sued for using the open-source stuff, if I got this right. (IANAL) Patented stuff can be used as long as the owner of the patent doesn't seek to enforce their patent. Unlike trademarks, the owner of a patent doesn't lose it if they don't enforce it, and also unlike patents, the patent holder can choose to selectively enforce/seek damages from infringing parties. Does a company with as much market penetration and power as Apple really feel threatened by open source projects such that they need to threaten them with lawsuits, meanwhile not feeling threatened enough by them to use open source software? Patent holders, including Apple, could take the high road and say "While we own these patents, we're not going to attack or threaten open source products that use our patents because 1) we benefit from open source 2) we still have the advantage even if our competitors use the open source product that is using our patented technology". But they don't, I suspect because it's cheaper to set a precedent for the validity of their patent by attacking someone who can't fight back.