I appreciate your point and concede that in some cases of product shrinkage there maybe unintended benefits. However, this isn’t a tax but rather a financial windfall for the Coca Cola company along with a reduction in value for the consumer. It’s what appears from my point of view to be part of a larger trend in a country where food is already expensive comparitive to other parts of the world.
Did you see the case with Cadbury chocolate block shrinkage? Putting aside any doubts about Cadbury’s intention, if junk food manufacturers wanted to reduce price and portion size with a genuine and dedicated focus on providing better community health outcomes, I’m sure the behaviour would be viewed in a different light 
