It is not bizarre at all. I find bizarre, OTOH when people fail to understand the context of the phrase. It is not normal to overspecify a statement, when it is clear what is the obvious meaning: a normal modern consumer-grade CPU in a typical usage environment cannot work at frequencies above 5Ghz. And that is true.
As of 2014, the Guinness World Record for the highest CPU clock rate is an overclocked, 8.723 GHz AMD Piledriver-based FX-8370 chip