"Luxury" sounds not very appetizing. 

I'm all for fine wine and cheese (which can be expensive) but usually word "luxury" is applied to something meant to display wealth, like gold-plated bathroom fixtures and your secretary holding your towels. Inedible things you won't buy in sane mind.
"Maggots" is worse.
"Larvae" is better:)

For distibution of lactose (in)tolerance see pictures here:

https://en.wikipedia.org/wiki/Lactase_persistence

It is a relative novelty. That is an old invention is a gene that encodes lactase and enables you to drink milk. Another old invention is a gene that switches off the previous gene in adults and makes them lactose-intolerant. And recent invention is simply breakign this latter gene.
As it is a recent and very simple mutation with obvious benefit that gives strong selective advantage - it is famous. But there are only few regions where most people have it. 

I mean that it should go without saying that insects are lactose-free, dairy-free, and gluten-free. Insects never have lactose, dairy, or gluten. But it sounds better to say that the ice cream is lactose-free than to say that it has insects in it.