Just because it's in a ToS doesn't mean it's reasonable or immune from complaint or criticism. I can require in my ToS that everyone who uses my Awesome(C) API to do a headstand on first access, that doesn't make it reasonable.
It's completely unreasonable, to the point of being WTF-worthy, to require the app which accesses the API to be in a certain language.
Seriously. I'm having trouble phrasing how dumb this is. As long as the app can generate the appropriate requests and serve the appropriate data, who cares? What possible legitimate reason does Google have to decide if the app is written in HTML5, Java, INTERCAL, brainfuck, or lolcode? Why provide an API at all if you're going to do platform restrictions?
