I think this is how a lot of enterprise software is sold. Potential customer says "it's missing x", sales person says "we'll build x in two weeks", product is sold, devs have to figure out how to build x in two weeks.
I think you have a few minutes to delete comments, but as soon as someone replies to you that link goes away.
I think it's a good thing, because often there are good comments in response to downvoted comments. Letting people delete comments would make the discussion hard to follow.
That stuff is not possible if you have a sandboxed app from the Mac App Store.
Sure, if you download software from the web, it can do whatever it pleases.
But if you download apps only from the Mac App store, you should be safe.
On iOS, Apple checks all your software. On the Mac, they give you a choice: If you want "safe" software, go to the Mac App Store. If you want any software, go somewhere else.
The sandbox isn't as complete as on iOS, but the stuff you listed requires special permissions and confirmations when you get your software from the Mac App Store.
That probably doesn't work for physical products.