Why does Mac OS overwrite whole folders rather than merging their contents? I’ve noticed that if I have two folders of the same name but different files in each, copying one on top of the other (eg: from different parent locations) will cause the contents of the first folder to be wiped out by the second. Windows does not do this; It merges the contents of the two folders, making the operation far less destructive. On Mac it feels very risky.

Why is this?
Is it an option which can be changed?
Merge two folders with the same name

If you have two folders with identical names at two different locations, you can merge them into a single folder.

Press and hold the Option key, then drag one folder to the location that contains a folder with the same name. In the dialog that appears, click Merge.

The Merge option appears only if one of the folders contains items that are not in the other folder. If the folders contain different versions of identically named files, the only options are Stop or Replace.