Ok, I'm pretty much convinced that you're just trolling but I'll bite once more. It's a long stretch to say that there are thousands of other apps that connect with Evernote when what you're really saying is there are tools to connect thousands of other apps to Evernote. Having used both of those options I still find working directly in Evernote far more convenient for most of my needs. It seems there are a lot of other people that feel this option would be a great addition as well. Besides, I would still debate the "thousands" assertion if only on the basis of enumerating the number of usable apps that make sense to connect to Evernote. Literally speaking, for it to be "thousands" there must be at least two thousand. I don't think that list exists. Perhaps you're argument is that every application ever created can connect to Evernote through external applications and therefore no one should need to use Evernote's UI for viewing, editing, or creating notes if they don't like how it looks. Doesn't that seem silly to you? If not, see my first statement.
However, this is really beside the point and IMHO you're using a straw man fallacy to ignore the crux of this thread and our request to the devs. You don't want to use an Evernote dark theme? Awesome for you. Obviously a lot of other people do and your argument against that amounts to stating "that's not how I want Evernote to look so the option shouldn't exist and if you want a dark theme, don't use Evernote, use something else and sync that to Evernote". I feel that's being obtuse simply for the sake of it and that is something trolls frequently choose to do.
If you think you have a valid argument against other people being able to use a dark color theme in Evernote I'd love to read it. Otherwise I guess we'll just have to agree to disagree.