Not only is it a chillul Hashem but it causes more chillul Shabbat as police will have to come. Not to mention throwing rocks it itself chillul Shabbat besides the fact that someone who does that is a potential murderer c”v.
They would do much better if they would invite the customers for a meal (I actually knew a couple who went to live in Tel Aviv and went to Dizengoff St of Shabbat nights and invited people to dinner).