My guess is that someone read a book, and it said "feed them crickets, mealworms, and zophobas"--and they assumed that meant everything else was off the menu.
Might seem odd, but I've encountered that assumption before.
Silkworms, wax worms, butterworms, feeder roaches, grasshoppers, stick insects, and mantids are all feeders that are perfectly fine for leos. If you can raise it, and it's non-toxic, it can be fed to an insectivore.
Using lobster roaches to replace crickets has been great--I raise my own, and I don't have to deal with stinking, chirping, jumping creatures. The roaches are odorless, quiet, and easy to care for--and extremely prolific.
Also, with a minute amount of risk, I collect "miller moths" in season here. These fat-bodied army cutworm moths form dense swarms early in the year, then migrate up into the mountains. They return later to lay their eggs. Running a butterfly net through a swarm can net you 25 moths at a time. The folks here understand that trying to poison them is pointless...no matter how many you killed, more would hatch, so all you can do is just wait them out. Thus, they are fairly safe to use as feeders (never had problems). Any herp that can stuff one in its mouth seems to adore them. (Using these is actually fairly common among herpers in this area--they're a nutritious feeder, and free).