What's the logic for vegetarian special meals on flights??

After yet another flight with a subpar special meal, I need to understand once and for all the logic behind how the airline (or is it the crew?) decides what meals to serve, specifically for lacto-ovo vegetarians.

I don't eat meat or fish, but I very much love eggs and cheese. Yet, time and time again, despite requesting a lacto-ovo meal, I get what closely resembles vegan food. It's usually some grains with veggies, vegan-friendly desert and sometimes even vegan butter. I have tried getting the Indian meal and that's been hit or miss with the quality too.

What's interesting, though, is that most airlines now offer a choice of at least 2 dishes during their regular service - one of which is usually vegetarian - with much better-looking starters, mains and desserts. I'd say I regret ordering the special meal 8 times out of 10 these days and only do it on the off chance that this specific flight won't have a veggie option.

My question is - why do they even bother giving someone who has requested an LOV meal something different to what's served in the standard service in this situation? I'd totally prefer just eating some pasta and real cheese instead of a dry bed of rice and some steamed veggies. It just seems not worthwhile for the airline to go through the trouble of giving someone a special meal that's more restrictive diet-wise when there's a meal that perfectly fits their criteria already available.

I'm sure everything has a reason, but it just seems so odd to me!

EDIT: to clarify - I don’t feel entitled to the exact meal I ordered or any special treatment. As someone with a dietary restriction who travels to many meat-heavy countries, I’m very used to finding something I can eat and enjoying it. I just wanted to see if there was a rhyme or reason to why special meals are the way they are so that I could adapt better.