It need not be moralising at all. In many countries for pretty much every "life changing" contract such as marriage, buying a house, changing the will, etc. there's a cool down period that tries to prevent being rushed to do such things.

Also here in (some cantons of) Switzerland, during the month of notice you have to give to get married, the names of the couple is published so that people can protest the marriage if they know it's not a legal one, which is for sure something some people can find odious but it's not done for moralising but for practical purposes.

The reason is not a moralizing one, it came into being when the registries were less than perfect to avoid bigamy. It probably could be abandoned in the present day without any loss of functionality but it definitely was not codified into law for moralizing reasons.

Isn't bigamy typically a religious moral?

No, it is a legal one. There are pretty substantial consequences, for instance with inheritance and paternity.

Isn’t avoiding bigamy moralizing?

Not necessarily pertinent here.

Think of it this way: If bigamy was legal, you would still want to at least know if you were the only spouse or one of several. A lack of reliable and readily accessible records makes deception all too easy.

Marriage is a contract. Agreeing to a mutually exclusive arrangement only to find out it isn't is a problem, even if you don't think polygamy should be illegal.

I don't know what percentage of the time bigamists are deceiving their spouses and married to someone else "behind their back," but that's certainly a version of events that happens and it makes everyone involved pretty unhappy to find out they aren't the only one.

This is typically done by someone who travels for work. It was much easier to pull off before our current state of global communications.