It’s awfully easy to “fake” being a Christian for entrance requirements. I attended a private Baptist college my first year and my roommate was a raving heathen, although a “Christian testimony” essay and recommendation had to be included with each application.
Additionally, it’s a balancing act for a small Christian college, which turns away potential students at their own fiscal peril by screening them too stringently while trying to ensure a genuinely Christian student body. They pretty much have to take their word for it, absent any conspicuous evidence.
Christ warns against hypocrisy because it is so common.