There's being sanctimonious, and then there's simply telling people when they're being silly.
For example, I have very little problem with people driving at a fair lick on a well-sighted B-road in good conditions. However, doing 85 on the motorway or exceeding a 30 at any point seems utterly daft as that's exactly where you're most likely to be caught. If you do so, and then get the letter through the post, as long as you're not moaning about it (and in fairness, I don't feel the OP actually is) then you'll have no issue with me.
The more people that speed in places where it's bloody obvious that there's a chance of being caught (main routes, 30/40/50 limits, anywhere it would be very easy to park a camera van), the more likely they are to keep adding cameras. The country won't always be skint, and at some point they'll start funding these again with a vengeance as it's easy money. If everyone stopped speeding in silly places, then overnight this would become a huge loss maker for the authorities and they would stop funding them. Simple as that.
Every time someone gets caught, they make it worse for the rest of us.