I think that assumptive text has a lot to answer for. It would appear that we put down or read what we think was said but never read the correct information. How many posts here actually answer the point as it's put down. Or more important put onto paper succinctly, without the btw,lol, and all the other gobbildie gook that goes with it.
You will always get the odd one but if that ticks you off then maybe the casting call system is not for you.
If you are getting a lot then it may help if you look at what you are offering by way of a shoot in your casting calls. There are many thousands of shoots happening so other people are having no trouble arranging them.
Models shooting the levels you are asking in your castings may not be able to shoot at their home, may be uncomfortable with the idea of location work and may expect to see quite a few references and even may take a view on quality of the photography before they may consider such requests. A lack of serious offers will obviously make the silly ones seem more annoying.
Models that shoot at those levels have their own requirements to take on shoots and maybe you need to consider adapting your requirements - either levels or book established studios.
I put in a casting call recently, and bearing in mind I'm in Cornwall, the first reply I got was from a model in Southampton. To be fair to her, though, I never said in the casting call that I was looking to shoot only in Cornwall, so I immediately amended it to say this. The next reply was from a model in Merseyside!! The final one was from a Devon based model, but as that's only in the next county I decided to make the trip. I was so glad I did as she was a lovely lady and we had a brilliant shoot. And none of the models' replies annoyed me, they only frustrated me in the instance of the first two as they were both models I'd happily have worked with if they weren't so far away. Speaking personally, I'd rather have any number of inappropriate casting call replies than none at all.