Your literally saying "People are eating and that kids having fun" so yes you're 100% been a grumpy killjoy, As long as no litter is left or damage done (Which are both criminal offences) then their business is their own and certainly not your business in any way, No wonder you didn't say anything because i can imagine their reply just as you clearly did by not saying anything to them (The two words you'd get begin with an F and an O)