Well, it depends if the U.S. Constitution means anything to you or not. And, actually the Democrat controlled Senate hasn't passed a budget, not Obama (Though Obama is of the same party and hasn't said anything to them).
Because democratics are never forthcoming and honest, it's difficult to answer your question. A fairly sound explanation is that they don't want the American People to know how they are spending your tax dollars.
Does it matter? Well, it depends on what is important to you. If you feel that the government should obey the law just like we have to, I would say yes, it does matter. But to some, it's so important that we have a certain political party in power, that they can't let it matter to them.
Here are some questions for you:
Should you trust Obama/democratics, or government in general, that much with your money?
How would you feel if Mitt Romney/republicans hadn't passed a budget in 1000 days?
If it was Romney/republicans, would you get riled up because your friends or the media told you to?
Remember, it doesn't matter which party is in power. Those would still be your tax dollars that would be unaccounted for.