The problem is the implication that "fun and gaming strategies are legitimate pursuits for a child" are only present in games with in-app purchases. That makes no sense at all.
I didn't take that implication away from the author's overall post or the specific sentence that you're referencing. I find it odd that anyone would. For someone to write enough words to be so specific as to remove all ambiguity would not make for interesting reading. Instead I choose to interpret the meaning of their limited words charitably.