I agree with you to a certain extent. If I were rockfishing on an ocean beach I would probably wear one but that should be up to me and my own "risk cause analysis".
My gripe is , if I'm standing on yarra bay breakwall with the ocean as flat as a tack, with a fishing rod in my hand I can be fined.
Some bloke standing next to me with nothing but speedos on will not be fined.
What does it matter if I'm fishing or not?
By the way , this thing is suppose to be a "1 year trial" yet they state fines will come into affect from december 2017.
This suggests they already know it is permanent.