I find this remark to be awfully arrogant.  I would venture to 
say that there are many people who are Christians now, who at one
point in their lives had no intention of ever becoming a Christian.
I was certainly one such person.  I am quite thankful that there 
were Christians who were willing to continue to talk to me, despite
the appearance that it might have been a waste of their time and 
mine.  (I even married one of them.)