That is a fair way of looking at this, but in the present situation, I would consider the decision about whether to include a Facebook share button on one's homepage (or more generally the question which third-party code you allow to run) as a fundamental question of operating a commercial web site. From an economical perspective, you can't blame anyone for doing it, but if you are, don't claim the moral highground either.

I might not be up to date, but a few years ago when I dealt more with this I found ways of creating a facebook share button that mimics the functionality of the real thing without adding facebooks javascript to my site. It was some special URL if I am not mistaken.

Not all facebook share buttons might be created equal.

This is, and always has been, trivial to do. There’s a URL scheme you use to generate a “share this” link to Facebook with the appropriate variable inserted. You can style it however you like.