Clothes carry a view of earthly status that would detract from the spiritual character of the figures.
The human form is beautiful and it is only the corruption of our minds by the prudish that ascribes any shame to nudity. Thank goodness art can rise above such base notions.
Clothes are also subject to fashion, the naked human form is timeless; just as the religious messages being depicted should be.
So, no, it is not wrong to sculpt (or paint) such figures 'au naturale' and yes, it is wrong to alter works of art in the manner described.
Regarding Renaissance worldview, I cannot comment as I don't know enough about their worldview. Just in case anyone reading this hasn't come across it, I will addMichelangelo's famous quote with which I wholeheartedly agree:
"What spirit is so empty and blind, that it cannot recognise the fact that the foot is more noble than the shoe, and skin more beautiful than the garment with which it is clothed?"