As a nation we have grown accustom to certain tax benefits, including the exclusion of health insurance benefits from income.
For most of my life, my health insurance has been provided by an employer (whether my own employer that of my parents or husband), so I've certainly benefited from the provision. But just because I benefit doesn't make it fair.
This is one of those concepts with which some people struggle. When considering the issue, an experience from high school comes to mind. It was back in my semester of Economics. During a discussion on Affirmative Action, a friend of mine spoke out against it. To her arguments, the teacher countered that she should be in favor of AA because it would likely help her (as a white female).
So that teacher lost all credibility with me at that point. Just because something helps me doesn't make it right.
For a good explanation for why it is fair to tax health insurance, I recommend the Taxgirl's post.
Of course, both the tax code and government spending are full of provisions that are not exactly fair, so maybe this isn't the issue to "straighten out" first. And the whole discussion may be irrelevant, since the measure is stalling out in Congress (see the latest post from Taxgirl). But we shall see what we shall see.