Possibly down to the types of book I read, but I notice it way more in Sci-Fi than in Fantasy. Though that could be because a lot of the SF I read is way more liberal than I am. As an example, I almost DNF'd Elizabeth Bear's new book when it called me a bigot within the first chapter.
As a general rule, I'm fine with having open themes. A lot of the Military SF I read is openly quite preachy about duty and honour, but it informs the story rather than getting in the way of it.
I must also admit, since I did my degree in creative Writing, I tend to notice things like this a whole lot more than I used to.