You are right, copyrights are about copying. Copyright licenses cannot address software patents any more than they can address US export restrictions, trade marks, contracts, or any other international or local laws that might deny you some freedoms. Theo cannot grant you rights to Microsoft's or Cisco's patents. What he can grant you is rights to his code.
Now you can try to "address" software patents e.g. by obligating distributors to grant rights to their patents, but that is a restriction; it might be giving someone more rights, and by the same token is taking more rights away from someone else! More importantly, that would be a restriction imposed by the copyright holder, rather than an external restriction imposed on you by a third entity the copyright holder does not control.
OpenBSD does not want to impose such restrictions on you or anyone else. They make their code free.
You seem to think that OpenBSD or Theo simply disregard patent issues because they hail from Canada. Maybe you should learn about CARP[1][2], or figure out why many of the ports' Makefiles have a line like this:
PERMIT_PACKAGE_CDROM= patents
[1]
http://www.openbsd.org/lyrics.html#35
[2]
https://en.wikipedia.org/wiki/Common_Address_Redundancy_Prot...