This is full insanity. Plenty of other sports being played and aren't banning hugging among teammates. Even the NFL didn't ban hugging this past fall and they actually did ban celebrations after touchdowns for a few years.
Maybe something to do with the riders are sometimes getting together from races in different countries and once they have finished their race, they will be flying off to other races in different countries again. It only takes one or two to get the virus unknowingly then take it to another country. In the likes of football NFL etc, those sports are staying in their own country. (apart from the odd European match in football). Yes, they are in bubbles but it has been shown that bubbles don't always work.