This all depends on the definition of a 'recovery ride'.

UCIMBZ is correct that riding on an off day doesn't clear lactate from your system, that was happening from the moment you created it and is finished very quickly afterwards. After a hard ride is finished your body needs to repair and strengthen muscles and restock energy to your muscles and liver. That happens while you rest.

If you want to ride on a rest day you are smart to keep intensity and HR down as it let's your body repair and strengthen itself. The ride doesn't help you recover, but if you take it easy enough it allows recovery to happen.

Pros ride on rest days during grand tours to stay loose and keep a rhythm. Many who don't report that their bodies go into a 'slow down' mode and it is hard to get going again on the next active day. They aren't 'recovering', they are attempting to tell their system that it still has work to do.