itch.io is a mess. TWP isn’t on there either. If you’re on itch.io, you need to make your own Windows installer (Steam/GOG do this for you). Not rocket science, but it’s a hurdle. And you have to set up your store and make a bunch of images in formats very different from Steam. Puting a game on a store is a pain in the ass. Plus, you probably have to do a different build if you’re doing anything with Steam APIs (achievements). Now you’re managing 2 builds. And you have a new place to monitor comments and do support for.
Read this the section “Zero Friction for Developers” in here: http://www.fortressofdoors.com/so-you-want-to-compete-with-steam/ This is real and every developer I know hates it.
I think it’s unfair to say he doesn’t care. He just doesn’t care about the same things you do.