This is probably the most controversial topic that I encounter on a regular basis because there is a lot of debate over whether white chocolate is 'real' chocolate.
Chocolate is made from cocoa beans, but cocoa beans can be separated into cocoa butter and cocoa powder.
white chocolate = cocoa butter + sugar + milk powder
If cocoa butter is a bi-product of a cocoa bean, by my definition it is chocolate.
The controversy arises because a lot of products marketed under the illusion of being white chocolate are actually confections because they are made with other oils taking the place the cocoa butter (eg., vegetable oil, palm oil, sunflower oil). Commercially-made white chocolate only has to meet legal standards set by the food administration of cocoa content to be called white chocolate. In Canada, white chocolate must contain a minimum of 20% cocoa butter, 14% milk solids and 3.5% milk fat. This might explain why many people think that white chocolate tastes super sweet and oily because there is a lot of room for non-cocoa ingredients.