It is entirely reasonable to provide programming tasks or whiteboard interviews or whatever in lieu of going through someones personal project.
Using your own lifestyle and tastes as a benchmark is what riles people up. If side-projects are the measure of the man, then there is an expectation of how people should spend their free time.
I believe the polarization is coming from how this is expressed, specifically pegging side-projects as the determining factor. People can find joy in their work (programming in our case), but not necessarily want to do the same thing in their free time.
This is likely biased as it is coming from someone with no personal projects though :)
Plural of anecdote is not data. The principle that "the more work you put into something, the better you get at it" works in general.