It is a term frequently used by leftists when they don't want to use the term 'racist' because

• they are saving that term up for something else
• they have already used the term racist and want to appear as though they doing more than regurgitating the same slogan
• they are hoping that you don't know what it means and will make an ass of yourself on national television.

Pauline Hanson appeared on Sixty Minutes and responded to 'are you xenophobic?' with 'please explain?' The move was calculated to make Pauline Hanson look stupid and uneducated. It worked - she did. More importantly though it made interviewer Tracy Curro look like a member of the intellectual elite. Pauline picked up many votes that night.