I would not feel guilty, no. There is a lot of hypocrisy surrounding environmentalist types. I mean, lots of them say they wouldn't drive a cadillac or whatever, but then drive around in vans cos it fits their look, or worse - go travelling around the world, using jets even if it's for a good cause, the usage of jets usually outweighs the good they do and they'd have been better off donating money to charity. Most of them only care about their self concept as a morally superior person. I care about the environment as much as anyone, but there's no point losing sleep over it, just make smart lifestyle choices that don't affect you too much and dont pretend you care more than you do.