For many people who voluntarily limit their diets, texture is often a huge issue. Many people consider me a very picky eater because I won't touch salads, but that's a texture issue. I also eat a lot of things that many "normal eaters" won't touch (organ meats, for instance.) Either way, I choose from what is available that I'm comfortable eating, and I don't whine about what isn't there. If there is nothing I can stomach, then I politely fake not being hungry and make myself something later, when I'm alone. I'm an adult, and what I eat or do not eat is up to me alone. If you like to cook, then cook -- it isn't anyone else's responsibility to cater to my limitations.
Dietary limitations also tend to go hand in hand with the autism spectrum; almost everyone who is on the spectrum will limit diet in some way, most often due to texture or odor. Also, sticking with the "safe" when eating in front of strangers is often a defensive action for people who are socially awkward; they don't want to have to deal with possibly embarrassing themselves if confronted with something that they will not know how to properly eat. If you eat familiar foods in such circumstances, you are free to concentrate on other parts of the interaction.
FWIW, my DS22 once ate something new at an extended family holiday dinner, and it disagreed with him -- violently. He was 10 at the time, and he made a mess that distressed everyone quite a bit. Guess what he will no longer do at a formal dinner? That's right, eat ANY unfamiliar food. Twelve years later, that humiliation has stuck with him, and he will not take a chance on a similar incident ever happening again.
I think it's rather bizarre to extrapolate that just on the basis of one "childish" meal (your implication, not mine), that a person must be childish or timid in all aspects of life. I really think that's taking if-then reasoning a wee bit far.