I don't believe shouting at other people about their dogs behaviour is okay. But I also don't think puppies or dogs should run up to other dogs without first checking in with their owners. Here's why..
1. If my puppy is told off by another dog, then they are likely to be worried about meeting other dogs in the future. This may cause them to be overly playful in an attempt to compensate for their anxiety about what might happen - so it looks like they're having a lovely time, but actually they're quite unsure in a social situation. Worse still, as they go into adolescence they may become fearful and react by barking/ lunging or growling at other dogs
2. I don't know the other dog - I have no idea of the history of that dog or how it feels about social situations. I don't want ANY dog to feel stressed or anxious, and I really don't want my dog to put another one in a situation which makes them feel that way. So if the other dog is on a lead, or minding its own business on the other side of the park and the owner isn't making an effort to interact with me, then I will give them a wide berth.
3. I can't control other people's responses to situations, but I can control mine and my dog's behaviour. Which means that I can avoid walks which leave me feeling anxious and stressed, by taking a cautious approach when I bump into other owners. More often than not, there's no need to worry and dogs will say a quick 'Hello' and carry on their way.
4. Small puppies usually recall well because they're little and they don't want to go too far. But if my pup gets into the habit of running off to say hi to every dog we see, then when they get a bit older and more independent of me it's likely to be difficult to persuade them that they need to come away when called. So it's a good idea to protect your recall away from other dogs whilst your puppy is still reliant on you
Today I'm grateful for how well my dogs check in with me before meeting & greeting every person/ dog they see. It saves me a lot of stress!