It isn't really good or bad. People that thought they could somehow get away with not paying taxes in the US are naive as hell.
If anything I think overall it is good because they clarified that you can indeed pay a lower tax rate for long term gains.
I doubt this news is the reason for bitcoin's price being down, it has taken a hell of a beating lately and been extremely volatile. I wouldn't assume that this news is even affecting the price.
Obviously bitcoins would have to be taxed, and to be frank I loathe the people on this forum who are always saying "screw the NWO government, Alex jones is my hero and they'll never catch me!" But the tax code renders bitcoin as a currency useless. It's still fine for making big purchases now and then, but if you wanted to walk around a city and use it like cash, buying lunch here a few drinks there, dinner here...it turns into an accounting nightmare.