wow that's weird, did you get in touch with them and ask why ? do they see this as a western definition for example, do they don't see the need for it ? or they already know it and interested in knowing more about something else
you can make a quick questionnaire asking all participants ( just a quick multiple choice questions and one optional essay if they want to write more ) like why did you choose this .... why didn't you choose this track.... and so on
so you can have an idea may be ?
it is really hard to tell why ? also who are the people signed up ? from where ? age ? number ? to know what this sample represents