Contrary to popular myth, the purpose of speed enforcement cameras is not to generate income. Rather, it is to enforce motoring law which stipulates that exceeding the speed limit is an offence.
When drivers are fined for the offences of drink driving and mobile phone use while driving, the fines are not seen as a “cash cow” but, quite properly, are penalties for having broken the law. Why should speeding be perceived any differently? No-one is obliged to speed any more than they are forced to drink and drive.
People often adopt a different stance, when one of their own is maimed or killed by a driver who could not pull up in time because of their speed.