Hi,
I think you have used the tag leisure=horse_riding incorrectly. The tag is meant for complete riding centers and not for buildings within a riding center. You have mapped nested riding centres within already mapped riding centers. What is this good for?
1. https://www.openstreetmap.org/way/70173787 (ASD Calzà Performance Horses) is a building inside of https://www.openstreetmap.org/way/1243408396 (Calzà Performance Horses)
2. https://www.openstreetmap.org/way/76909736 (Club Ippico PratiSaiano) and https://www.openstreetmap.org/way/534672982 (Club Ippico PratiSaiano) are buildings inside of https://www.openstreetmap.org/way/1243702673 (Pratisaiano)

You have also removed the building tags from the buildings so that they will be no longer rendered as buildings on the maps.

Please have a look at:
https://wiki.openstreetmap.org/wiki/How_to_map_a#Riding_centre_(equestrian)
https://wiki.openstreetmap.org/wiki/Tag:leisure%3Dhorse_riding