The app had been rendered useless, anyway, as earlier Foursquare revoked its API access. Because of that, the developer removed it, rather than Apple banning it.
At least, that's what the Russian developer of the app, i-Free Innovations, said in a statement to the Wall Street Journal.
As the developer pointed out to the WSJ, the app was using publicly available data. The problem, as we would agree, comes about if users didn't lock down their privacy settings enough on Foursquare and Facebook.
The developers said that they will continue development of the app, and intend to limit it to showing only public places and venues in a user's area.