This must be how things like some alternative medicine and anti-vax start: Things like feeling healthy and your computer being slow can be very subjective.
The author appears to be technical enough to know that there is something called keystone on his computer, but not technical enough to benchmark and investigate further. The name keystone sounds kind of nefarious, so it makes sense that someone would be able to convince themselves that it makes their computer slower.
Well yeah, because "my kid has autism and his also got a vaccine so obviously that's the reason my kid got autism" is exactly how it gets started because they heard about that paper (or rumors thereof) that has been debunked a 1000 times over in the medical literature but now it's a part of folklore and almost impossible to kill like other superstitions.
The author appears to be technical enough to know that there is something called keystone on his computer, but not technical enough to benchmark and investigate further. The name keystone sounds kind of nefarious, so it makes sense that someone would be able to convince themselves that it makes their computer slower.