True, but in this case it doesn't matter. The goal of a gas tax is to incorporate its negative externalities into the price signal, so that if burning a gallon benefits you by $1 but costs $1.50 in environmental damage, you won't do it. What the tax revenue is spent on is basically irrelevant.
Also not if the revenue creates a self perpetuating monster that will devour more revenue even when the externality is gone.
And while we're on the subject, doesn't it seem the least bit concerning that funding specific pork through taxes on diffuse externalities creates a pretty huge incentive to keep that externality going? Who came up with the idea to let the people responsible for eliminating the externality also benefit from the taxes you get from it?
The term itself was not originally pejorative (a barrel full of pork can feed a lot of mouths!) but it is generally used negatively by the press or cynically by certain government sectors.
The just thing would be to compensate/protect the victims who are on the receiving end of those negative externalities.