I would write to the airline. I can tell you from experience that unless you send in something in writing no action will be taken even if the action simply involves a generic apology or a talk with the crew member involved.
The comments are unacceptable but not alarming and you already see one post trying to explain this behaviour --- which really is a sad reflection on the state of the industry. This used to be a customer "service" business but there are many out there who will try and convince you that it is really a "customer enforcement" business and that fare paying passengers are really the enemy in disguise!