I suspect part of the reason is that Mr Letwin and his Tory colleagues have been taken back by the scale of the interference now, considering that they were last in power in 1997 - EU power has dramatically increased since then:
Constantly being told what you can and can’t do by Brussels is driving Ministers and No 10 deeper and deeper into the Eurosceptic camp.
Oliver Letwin, Cameron’s mild-mannered and cerebral Policy Minister, has become so frustrated by this constant interference that he has told colleagues he thinks Britain should leave the European Union if it won’t give us all the opt-outs the Government wants.
And it's not just the Tories who are frustrated either:
Letwin is not alone in thinking this. In one department, a recent meeting between a Secretary of State and a junior Minister ended with the pair agreeing that the only solution to the problem they were discussing was to get out of the EU.
Cameron’s strategy guru and close friend Steve Hilton is getting fed up with the way Brussels bureaucracy is blocking his agenda for a post-bureaucratic age.
...even the Lib Dems have been shocked at how much influence Brussels has on decisions that should be taken at a national level. Nick Clegg was appalled when officials told him that the EU wouldn’t allow VAT to be set at a local level.Was Clegg, a former MEP, really unaware of this? That an EU tax, controlled by the EU could not be set at a local level. If so, he is far more stupid than I thought.
But I little sympathy for ministers whinging, in fact it's more than a little irritating. It's fine example of wanting it both ways; you can hardly complain about having no power if you give it away.
They know the EU is a bureaucratic monster yet they sign up to more of it. They always vote for more EU interference, they always deny us a referendum on EU matters, not one of the 3 main parties advocates EU exit. If MPs and ministers think that remaining in the EU is good thing then EU interference is something that they will have to put up with.
If ministers, and MPs, don't like being powerless then they have a simple choice; get us out of the EU. And until then they should shut up.