It seems like attendant readers understands what the author was doing. They didn't say the definition explicitly, which would violate pep20 (explicit is better than implicit), but, considering this is an article in Outside Online magazine... I think we can accept this violation.

I can understand that you might think other people would be misled by the rhetorical structure... but I encourage you to not get upset at imagined misunderstandings on behalf of others. (Not that it's wrong, it's just makes your life a little less happy)