Most taxes are designed only to apply to a few people. It makes it easier to get away with creating and raising taxes if you can say "Well don't worry about it, it only affects maybe 5-10% of the people out there." The problem of course is that there's thousands of special tax rules so there's plenty of taxes that apply to everyone anyway.

The hybrid tax is just another example of how they want to create a special tax to apply only to a certain set of people. We already have a gas guzzler tax, although in their infinite wisdom, our lawmakers exempted the worst guzzlers of all; large SUV's. Now we'd have a tax on the most fuel efficient vehicles too. Pretty soon there will be a sedan tax, then a compact tax, then a sunroof tax, then a "cars with red paint" tax, and so on. Everyone would say "Oh, that tax only applies to a couple cars, who cars" but pretty soon there will be a specialty tax that applies to everything. It's basically the old military strategy of divide and conquer.