I agree with the spirit of your comment. I've bought plenty of Humble Bundle games, and have no issue with making in-game purchases available if it has no effect on gameplay.
However I take issue with labeling a subsection of microtransactions unethical. It may be annoying, and insulting, and even borderline illegal as regards false advertising, but there's nothing inherently or fundamentally wrong from a philosophical standpoint about charging extra for gameplay elements.
Now that doesn't mean that such publishers shouldn't go fuck themselves seven ways from Sunday, but that's another issue altogether.