In general it is used to belittle them. The same way it is used to belittle Justin. You aren't giving them the respect of an adult. Or it is used as a reverential nick name to be more personal Ralph, Hillary Bernie
I disagree that it is more prevelant amoungst female politicians though. I don't recall anyone ever using Danielle or Alison outside of trying to insult them. Kim Campbell was never Kim.
Funny enough in searching for Alison NOT Redford and found this post
http://forum.calgarypuck.com/showpos...postcount=1865
Where we had this exact same discussion before