When I worked at iFixit ~12-13 years ago most of the site was already aggressively cached whenever possible, and I’m sure it’s only gotten better since.
They are no strangers to bursty traffic. We would get insane bursts of traffic many, many times greater than typical wherever a teardown of a new iDevice was published shortly after release.
If Kyle and the devops folks there are noticing it, it’s definitely disruptive behavior.