Up until the late 19th, early 20th century, the term "insane" was both a completely useful and widely used medical term as well as legal term. It was the common term applied to people of "unsound mind:"

"Until well into the 19th century the word insanity was ubiquitous, not only in medical writing, but in that of the legal and lay world as well. It was the general term used by both professions and the public to refer, in the words of the 1851 Webster’s Dictionary, to the "state of being unsound in mind" and "applicable to any degree of mental derangement from slight delirium or wandering, to distraction." *

Screening measures are a valid tool to help people determine if they seek help. More than 1/3 of the people who take the Sanity Score receive scores that indicate no specific concern reaches a sufficient threshold to recommend talking to a professional, so indeed, it is helping people make such a determination.

Thanks for your feedback about the name and its intended purpose.

DocJohn

* - http://www.jaapl.org/cgi/content/full/33/2/252