I think I know the answer to this and need to trust my own gut, however ...
Situation 1: dog trainer shouted at my dog for doing something
Situation 2: I was advised to harshly reprimand my dog and avoid them seeing an animal they were barking at by obstructing them
Both were professionals with a good reputation locally.
My stance tends to be rarely to tell my dogs off as such, reward for good behaviour and try and avoid or ignore bad behaviour or ask for a more positive one instead.
There are exceptions, because I'm human! - if my pup jumped up and hurt me I'd probably shout out in pain - or if they were about to push past me to get to something dangerous in the food bin, I'd say a harsh 'no'.
Generally though, I don't want to shout at them. If they are being stubborn or bolshy, I will be firm but not loud. They are not lap dogs and come from working heritage.
Am I being too feeble? Out of text book and in real life, is it necessary to raise a voice? Barky dog would have continued to bark whether I shouted at them or not.