These are just the first that pops up if I search for 7700k vs ryzen in gaming.. - so aparently you can no longer say that in every video you seen the ryzen were better for gaming..
Benchmarks can actually favour the multi-cores as they tens to be based around testing gpu and cpu power combined, though in actual gaming performance few fast cores is simply better, and the reason is simple, game engines are rarely utilizing loads of cores.. it's been like this always, and while we have expected it to change for a few years, it hasn't. It is getting close, and with the new multi-core cpu's being able to run fewer cores at a higher speed when needed they are closing in.. The important thing to remember is that for things like rendering or compiling media, a threadripper is likely to be up to 10 times faster than a 7700K, so in no way is the new ryzens bad by any means, but saying they beat 7700K in gaming is just wrong :)
I hope that explains the picks for the build, in addition to those parts not even being there when the build was done (the 7700K also beat all the more expensive multi-core intel parts, as they just like the new ryzen, has core-count but not the core-speed to show for)
I guess you can't help with the Opinions of some people. A cpu is good for what you intend to use it