This article is dead on.
I’m a physician assistant (and erstwhile amateur entomologist), and I had a MRSA infection several years ago. It was the most instructive malady I’ve had to date.
The reason most people assume they were bit by something is that when a MRSA infection begins, it commonly starts in a microtear in the skin, often in a hair follicle. For the first day or so, the primary symptom is a raised, itchy weal—which appears EXACTLY like an insect bite. After that first day, it morphs into a pustule and looks more obviously like a bacterial infection. Thus, people (and many clinicians) assume they’ve been bitten by an insect, and that said bite later became infected. My own experience, and Occam’s Razor, tell me otherwise.
That being said, people generally find the MRSA concept extremely frightening. The vast majority of “infected spider bites” are MRSA infections which are contracted by merely coming into contact with the superbug through normal everyday activity. Yes, your environment can sicken and kill you. Even without spiders.