It's not really as clear cut as "staring makes you an asshole." I've found that in a workplace people will have wildly variable interpretations of the same event. The only solution is to work with mature adults who can assume good faith and work out their own issues. This almost never happens, so instead companies create hyper-sanitized environments where everything is against the rules.
While personally I think its creepy to just hang out and leer at them, it's not really against societal norms in any way.
It's not like these guys broke into the girls bathroom to watch this or something.
But I think it's impossible to really judge this situation without the context. Did other people decide to participate or was it really just two girls hula hooping the whole time? It boils down to was the mentality from the males perspective "oh hey, cool, people are hula hooping!" or "oh hey, the two attractive girls are hula hooping and I want to gawk at them!" The first one is fine, the second one is not.
The majority of your judgemental and passive/aggressive posts in this thread suggest otherwise.
I wonder what do you think about people who don't speak English or who don't eat their food with a forks but with other ustensils.
What on earth are you talking about?