Schubert, allow me to correct you, it might be a surprise.
Also, many of following states are Republics too and all western countries are considered to be liberal democracys, in fact, here is the link
https://en.wikipedia.org/wiki/Liberal_democracy In Europe, only Spain, Romania, Norway and Turkey have some sort of mandatory religious education.
In Norway such subject is called ’Christianity, religion and philosophy of life’ and it is going thru public discussions is it ’fair’ or not to be educated.
In Spain you might be excluded from such education if you bring the conformation that you are not religious, the rule which has seen objection as well.
In Austria, Italy, Germany, Poland, Portugal and in some ex Yugoslavian states, the pupils can attend such subjects at schools, but religious education is not mandatory, meaning that children can usually chose between religious or some sort of subject that teaches ethics (also not mandatory)
Belgium has the same model, but the classes are mandatory, one or another kind
Greece, Holland and Great Britain have different solution. The teachings about religion are included in some subjects which are not stricly religious
So, in Greece its called ’The history of religions’ , the Dutch have something that can be translated as ’Knowing of societys, with history of religion included and in Britain they learn about few different religions and its praxes
France, Hungary, Bulgaria and Czech republic have no religious education at schools at all.
The Switzerland have many different models, all above included.
In constitution of EU, there is no mention of religious roots or connections
.Is it a fairy tale for the US, I would not know, but its never too late to become your reality too