All those snarks. Should I feel patronised?

I write. I've always written. If I do it for myself, as I did for a long time, then I have nobody to please but myself. If I write for publication, I'm expecting someone to shell out their hard-earned to read my book.
That's when I have to care what people think. I'm not providing a service, I'm providing a product.
If my product is below par, ie badly spelled, grammatically wrong, unsatisfactory plot, badly produced and so on, then the reader has a right to criticise. Some (like the spelling etc) is fact - sort of - some is opinion (plot etc). But whatever.
If the criticism is constructive - ie tells me what is wrong, then if I agree with you, I have a chance to fix it in my next book. If it's destructive, ie just tearing the book down because of the reader's private opinions, then that's not much use to me unless lots of other people share the opinion, too. I don't write for one person, unless that one person is myself.
I will not write what the reader wants, and instructs me to write. I will write what I love, and hope you love it too.
Read the book. If you don't like it, say so, and say why, if possible, without nastiness. If you like it, say so, and why. I appreciate it.
I'll take your opinions on board, and I'll make my own mind up. Otherwise, I'll turn into a cardboard cutout writer, trying to please everyone but pleasing no-one.
But can't we be civilised about this? Or is that too much to ask?