The overwhelming majority of military personnel honoured by this cross (and not "structure" -- too shy or ashamed to spell 'cross'?), were indeed Christians. So, they have the right that they be remembered by their preferred symbol. If other military personnel, with different faiths, wanted to be remembered by their preferred symbol, so be it. Do it. But if they don't do it, that does not authorise the state to deprive them form their preferred religious symbols they want to be remembered by.