True. A bad bite, anyway. Most bites are not bad. The Wikipedia article is informative (
https://en.wikipedia.org/wiki/Brown_recluse_spider#Bite).
My understanding is that most people never see a brown recluse, even within their natural range. Those who do see them probably don't recognize them most of the time, because they're not especially big, because from a distance they look pretty much like any other brownish spider, and beause neither the human nor the spider generally want to get close enough to make a positive identification possible.
But it so happens that I've seen a lot of them, so I offer some trivia about that.
I saw hundreds when I was 12 and my father and brother and I were hired by a neighbor to tear down a shack on his property. It so happened that there were hundreds of recluses in the shack. I know because I was nerdy twelve-year-old with a fascination with wildlife and field guides, and I had a pretty nice little field guide with a good image and description of brown recluses.
I've seen many more of them in the house I live in now. I've been in this house for about fifteen years now. There are a lot of brown recluses living in it. I've seen many dozens of them over the years. The last time my daughter came to visit us, she found four or five of them during the week she was here. She's a little arachnophobic, but not too badly, and the experience hasn't diminished her enthusiasm for visiting We expect her to be back in a few months.
According to Wikipedia and other sources I've read, they rarely bite--generally only when they're being mashed against someone's skin hard enough to frighten them but not hard enough to kill them. When they do bite, it rarely causes any symptoms. When it produces symptoms, they're usually minor--most often sores on the skin; less often some necrosis of the skin.
The bite _can_ cause much more serious symptoms, but that's rare.
I had a bite once living here that might have been from a brown recluse. My doctor was skeptical, because the bite didn't look quite right. It produced a small, tender sore and a really large inflamed area around it. I didn't notice it at all until a relative noticed it on my back. That's consistent with reports of brown recluse bites: most often people don't feel the bite when it happens. Their fangs are quite small--usually they aren't able to pierce fabric--and the venom itself is painless; it's the later effects--if any--that become painful.
At any rate, I and my relatives seem to have reconciled ourselves to living with a large infestation of brown recluses.