I spell it "catalogue" no red line please

Ok, America has logical spelling, we've got metric, they've got spelling . Fine, but I get so annoyed when software tells me I've spelt "catalogue" wrong. I mean I'm not a good speller at the best of times, when I get a word like "catalogue" right first time it should congratulate me (imagine -- ding, ding, nice spelling! --) not put a little red line underneath it. And all this in spite of adding the NZ, Aussie and UK dictionaries!

This is an ongoing problem with all software! I guess what I can't work out is whether it's ignorance , callous disregard on behalf of the developers or a conspiracy by the printers of the Miriam- Webster Dictionary!!