IMO if your kids are near to someone who feels the need to release anger and/or frustration by use of expletives, and if you are so overly sensitive as to want to avoid your child experiencing life, then it's up to you to move away and/or cover their 'sensitive ears'. Remonstrating with someone instead is poking your nose in where it shouldn't be, and deliberately picking a confrontation with a stranger. Clearly misguided behaviour and an appalling example to set the child to whom you are making out you are 'protecting'. Simply don't do it, your views are your own, don't use them to deliberately start an argument in public because you want to feel you are virtue signalling to everyone.