If you are asking about yourself, then I would suggest that until the kids realize what is chalav yisroel and what is not, you can make exceptions when you are outside the home, but definitely don’t bring it inside the home. NEVER, ever say it is not KOSHER because that is not true, and if they see someone else eat it, they will think they are eating treif and will have the wrong impression about them.
As far as others are concerned, it is not fair to discuss or judge what others do, it is only fair to ask a question pertaining to your own situation. So if that is a choice someone made for their own family there is a reason why they made it and it is not up to us to question their rationality. Sometimes there is an item that the child does better with that is not available in chalav yisroel format. Sometimes it is very difficult to get a child to eat and if they eat something they like a parent is thrilled, so if they can get them to eat a yougurt with the chocolate crunch on top and that is OU-D and not chalav yisroel, that is really not an issue for others to yenta about.