Sample size is always relevant for discussing the meaning of pretty much any statement like that, bad citation. There are probably <20 people who use ZZ competitively. If you took 20 random CFOP users from the database you'd find that ZZ was by far the faster method. Does that lead you to believe that ZZ is faster now? No.
Personally speaking I think ZZ can definitely be faster than CFOP, it's just that it is much higher skillcap. I got to ~12 second average with ZZ after practising for a month when I was around 9ish at CFOP, and I'd barely scratched the surface of where you can go with it, and my EOLine was awful.