Some seriously hard problems in computer science: distributed programming (consensus, consistency, handling machine failure), parallel programming models, proving correctness of nontrivial programs, P?=NP.
Cmon, P?=NP is cache invalidation? Be serious.
It's not meant to be a literal, pedantically correct statement, it's meant to be an insight, and enough people think that it is that this quote gets repeated. By all means print out your own page in 4-point text of what is and is not a hard problem and stick it on your own wall.
It's not insightful if it leads people to the wrong conclusions. It would be more insightful to impress on people that CS is a large and diverse field with more hard problems than can be reduced to a single pithy saying.