Personally OP, I believe the foundation of democracy in systems like the UK - and it's a very good, robust system - is the supremacy of Parliament.
I'm not a fan of democratic nation states being bound to organisations that exist outside of the nation state and can over-ride the lawful decisions of Parliament and the courts - the bodies ultimately answerable to the voters. I think it's anti-democratic in a fundamental way.
It's also superfluous in a sense. Clearly no European nation will stay in an organisation like that unless they overall agree with the principles it espouses. If it's coming back regularly with rulings that are not acceptable to the people of their nation, they are going to have a moral and democratic obligation to leave.
On the other hand, if they do agree, there's no point to it - it's just adding another layer of bureaucracy, they could come up with the same kinds of laws and rulings domestically.
In terms of this ruling specifically - it seems to me that telling nations that if they accept a refugee, they are now legally obligated to accept their entire extended family is grossly over-stepping, and also going to create all kinds of trouble down the road in terms of European countries being willing to accept refugees. That system is already under stress, I think a ruling like this could easily start to tear it apart.