The other owner was completely out of order and should have had better control of his dog.
Weimaraners are usually as you said a friendly bounding playful dog. However there are exceptions.
Just like occasionally there are Huskies that don't like all humans.
Two things I would say, neither are criticisms just observations from my own experience.
First, when a dog is on lead they may attack other dogs even if normally they are friendly.
It's the fight or flight reflex.
If they are off lead they can have a sniff and if they don't like the other dog they can simply run away.
However on lead they cannot run away and so some dogs will may snap at other dogs to say "I don't know you so stay away because I can't run off"
Unfortunately for us Husky owners they MUST be kept on lead
Unfortunately the other dog then tends to respond in kind and it can kick off.
My girly Echo (she's a white German Shepherd) is exactly like this off lead she is happy to run around with other dogs and mingle, on lead she acts as if she wants to rip their throats out and the owners too.
secondly lifting your dog up 'out of the way' does three things.
One, it stops your dog from defending itself.
Two, it raises them above the other dog which puts it in a position of dominance and so the other dog may attack even more to try to reassert its own dominance.
Three, If the other dog does try to attack the you are likely to get injured as your arms and hands are in the way.
When another dog attacks yours there is no wrong or right way to deal with it because it depends on the dogs and the owners.
You try to make it out of the situation with as little damage as possible.