AMEN brother!
Like you said....most people are doing a lot of "green" things around their house/workplace which make much more of a difference than running boats for a few months. (This is Canada, where you can only run a boat for 60% of the year in most locations).
My house has CFL lightbulbs, energy efficient appliances, low flow toilets, proper insulation/windows, etc, etc.
Not to mention my Ranger has a 4-stroke. I'm about as "green" as the Bass Boat world comes.
So...your darn right I am going to enjoy it and not feel guilty for it!