I'm talking the difference between needing to lower settings or not. A stable frame rate or not. Headroom in spiky performance games/scenes or not. And even if I was just talking about 5-10% performance metrics, then it would still matter as we're talking about hardware here. More performance for the money is always relevant.
Note that I'm not even bashing Ryzen here, I'm just correcting your statement that the CPU doesn't matter outside of high refresh/1080p which hasn't been the case for quite some time. The days of slapping an OC'd 2500k into a rig and being good to go with no concerns are gone. Games like the new AC games are core hogs, and they're not the only ones, and even in some of those games IPC matters because the main thread can bottleneck the rest of it.
Hardware purchases require choices based on a lot of factors, both brands have their place in that process.
