The editor you are referring to is the iD editor, i.e. a simple javascript editor running inside your browser.  It only has basic features and probably ignores that such tags are incorrect.

I found this mistake when running the Nominatim Q/A validator; Nominatim is the software behind the small Search box in the upper-left corner of the map.
(I was looking for something else but felt you might be interested to learn one more thing here.)
There are plenty of validator tools that check OSM data, such as Osmose or OSM Inspector, but it requires some experience to understand them because most tools have false positives.

Apart from that, your contributions are great.  Have a nice day.