Poilitical?

The news that the Catholic Education Service faces an investigation [a report here] over its encouragement to schools to sign the Coalition for Marriage petition [sign it here]  raises many questions, but one is very crucial indeed.
According to some commentators, the C.S.E.'s action contravenes sections 406-7 of the Education Act 1996 [here]  which forbid the “promotion of partisan political views in the teaching of any subject in the school”, and requires balanced treatment of political issues.
When does a religious issue become 'political?
It would seem the answer is simply when the government of the day decides it should - merely by contemplating legislation and initiating a consultation process as it is at present. Far from the Church intervening in a political debate, this is a clear instance of the State seeking to trespass on to an area which is not its concern. These sections of the 1996 Education Act were never intended to address a situation like this.
But it is in this way that even 'representative democracy'  becomes tyrannical and the rights of 'minorities' can be played off against one another and given priority according to the social fashion of the moment. 
It may be thought that is is hardly tyrannical to insist on a 'balanced treatment' of controversial issues, yet can it be right to insist that a Catholic school (or any other kind of Christian educational establishment) should be forced to present a case to its pupils which is diametrically opposed to its teachings, according to which the definition of marriage is not a 'controversial' or partisan political issue at all? The fact that these schools are state-funded is a red herring  - Christians pay taxes too.