Mealworm powder is catching on in health circles. I think the essential difference is that you never have to see the legs, shells, compound eyes, etc. that scream "Insect!". Grind these up, mix them into sauce or a stew, and I doubt I'd care, even if I knew the origin, just like I can see the inside of a slaughterhouse and can still eat ground meat.
A lot of what we eat (steaks, chicken nuggetts, hamburger, bacon) is dissasociated with the source form of the meat. This should probably be the inroad. If people get used to the idea that they're ingesting insects anyhow, then maybe the rest gets easier?
I was puzzling over how 25% protein could turn into 9% protein, but then I realised: that boiled number is including 70% water. Obviously there is no protein in water.
If you ignore the water, it's 29% protein. Alternatively, 25g/100kcal.
Aside from the other points made here, many bugs are ecologically cheaper to produce per unit of nutrition. A quick google brings up a (probably biased) article:
You're supposed to cook lentils. Also, turns out lentils don't even contain that much phytic acid from the start.
Finally, your teeth rot? How? I suppose if you didn't cook the lentils, you might want to chew and ruminate them in your mouth for a few hours (tip: no, you don't), which might be long enough for the acid to have some effect on your teeth. But if you consume them like normal, and apply some basic dental hygiene, you're going to have to explain to me how this could really affect your teeth worse than most other foods (which are usually also slightly acidic).
