Disclaimer: this is mostly conjecture on my part and based on domestic flights.

Lately it seems that there is always a vegetarian option among the meals so maybe they don't feel the need to offer it as a special option? (Won't help if your choice isn't available, though...)

I have been unable to get the standard veg meal option to stick on a booking - but all the other options do stick. So you could get vegan, etc. if you would like to be very sure you can eat something.