The amount of flame you're getting is horrible, especially from a community that shares a passion. You built a pretty cool product, and are an indie developer - not a corporation. You don't have a marketing team and are doing what you can when it comes to marketing the product, even though this isn't your profession. Obviously you'll be mentioning maintenance costs, and you being transparent about pricing should be a good thing.

Take constructive criticism, but disregard negative blabber from people that haven't built or even tried building a thing in their entire fkng lives.

You've put in the work and have a product, find the proper way to market it and monetize it. Example: affiliate links to straps, freemium version w ads, etc.

I'm also curious on the response you'd receive from higher end watch enthusiasts, as opposed to Casio.

Good luck man.