That's unfortunate. It seems like most people would want homepage sharing on their homepage, no?
The instructions in the Jetpack blog post about moving the buttons indicated that one could put them in the header or footer. If so, what would they do on a site's homepage? Shouldn't it then share the homepage link? Seems like a bug otherwise.
I could use the vendor ones here, but I'd just like them to look the same as the rest of the site.
I even attempted to use source of the button output and changed the URLs, but then they no longer functioned properly.
I'd also tried including a loop for a blank Home page, but it wanted to link to that page instead of the homepage.
Oh, well. I'll have to figure something else out.
I hope a proper means of homepage sharing is included in a future release.