The guide is optional on both sides, the publishing side and the consumer side. If Amazon makes it a requirement to have a guide in the epub they clearly didn't understand the spec.
Amazon doesn't make it a requirement to have a guide in epub, they make it a requirement to have a guide in mobi. Both epub and mobi can be made from OPF, they just have slightly different requirements on that OPF file set. You could easily generate the set of files required for epub, generate that file format, then add the one extra file required for a conforming mobi -- which is just a slightly different syntax than the ngx file, add one link statement in the opf, and recompile the set of files for a fully conforming mobi. But instead you blame Amazon for the fact that YOU are choosing to make files that will not work correctly on the majority of e-book readers being sold in the market. You could easily make them work if you wanted to, but you don't want them to work. Other web sites for books including sites for free books using basically the same set of tools that you are using, instead of making excuses and finger-pointing ARE making files that work correctly on the majority of e-book readers being sold in the market. It's not like this is a whole lot of work for you one way or another. It's just that you WANT to pimp the files you are making for Kindles.