Apparently Genre Novels Are The Easiest Types Of Books To Write...

I came across this blog earlier. By the looks of things, the main purpose of the blog is to encourage people to write a book. A noteworthy sentiment I'm sure, but that didn't stop me from being slightly taken aback by her/his thoughts on writing genre fiction:

Genre novels are written for entertainment; they come with labels, like mystery, romance, thriller, and historical. In a sense, they’re the easiest types of novel to write, because each genre has expectations. In a romance novel, the romance must be the center of the book, for example. In a mystery, there must be a mystery to solve.

Easier to write than what? Non-fiction books? The bible? Political journals? What?

As for the bit about having a mystery to solve in a mystery novel, well knock me down with a fucking feather, ya don't say? *g*