The US has this pretty weird civil religion where the constitution is the holy text and the people that wrote the constitution are prophets.
Most other countries don't have that. A lot of democracies don't even have constitutions (UK, for example). The US constitution is an interesting historical document, but it's just a collection of laws. There are a lot of things democracies have figured out since it was written. Amendments are basically impossible at this point because the canon is closed and American politics have evolved to make it structurally impossible.
It should be possible to argue that laws should be fluid without appealing to the prophets of the civil religion. You could, you know, just talk about why it's a good idea. Shouldn't that be more powerful than trying to guess what someone who lived multiple centuries ago would have thought about it?