Why then, can the public sector workers not be treated the same. If you don't like the levy, then opt out but your pension will be less.
Don't want to get into the finer details of private pensions versus public pension, but its worth mentioning the point that the government could not afford to lose the pension contributions and levies from PS workers at the moment. Between the two they must be bringing in a couple of billion in revenue.
If this went into a ring fenced contributory pension fund the government would not have this money to spend and public servants would be entitled to the state old age pension on retirement.