I for one would hear loud alarm bells ringing if I thought that anyone fostering (they are not trying adopt sandyRoe) had sufficiently entrenched views from what ever source - that would impinge on their ability to care for any child's personality and sexuality without fear or favour.
At a stroke, that encapuslates any fundamental religionists, any sexual bigots or any pursuasion - in fact anyone who cannot simply love a child unconditionally, without certain beliefs triggering a pattern of upbringing based on the beliefs of the carer, rather than the needs of the child.
This couple asked for a ruling - and they received one - it's a shame they didn't like the ruling they got, but the law must be obeyed, not agreed with.
I would question the suitability of anyone to care for a child if they have beliefs that countermand the simple ability to love and care for a damaged infant.
Doesn't the Christian faith preach 'Hate the sin, love the sinner'?
If that's too hard to practise, don't offer to foster children.