Some charity shops don't want books of any kind, but I've never heard of the ones who don't turning away cookbooks. Getting a bookful of recipes for a couple of quid is a bargain.
Having said that, I have far too many of them, as I enjoy flicking through them, but my children have none, as they just look things up on the internet. They don't have many books (they use kindles), CDs (they use Spotify and Apple Music) or DVDs (Netflix etc) either, and I doubt they are unusual in their generation. Maybe that means that they are hard for charity shops to shift?
I didn't learn to cook at school either - for some reason it was assumed that you didn't need to if you were doing O levels ? - and my mum hated anyone in her kitchen, so I taught myself when I got married. Like many, I started by using jars of sauces and other convenience food, and progressed to making my own as I got more confident. I also bought the pasta 'n' sauce packets when my children were old enough to make them up if they had friends round. They are cheap, quick, and virtually impossible to get wrong, so ideal for Playstation-playing teenagers with hollow legs.
If people judged my trolley when I was young and buying Dolmio, or older and buying dehydrated pasta in sauce, so be it - I make no apology to them, and don't expect one back for their being smug and self-important.
Oh, and one year there was a craze for making Skittles vodka, and my daughter wanted to make if for her friends (they were in their early 20s - not children?. She asked me to get the ingredients for her, so I wandered around the supermarket with four bottles of cheap vodka, four giant bags of Skittles and a loaf of bread. The judgers were out in force that day?