I think this thread highlights (for me anyway) just how badly fish (and goldfish in particular) are treated in comparison to other pets. Because they're not furry and cute, because they don't interact as much as other pets, because they are hard to look after with little reward then they're really treated as disposable.
A properly looked after goldfish will live for 20-30 years. Imagine what the reaction would be if the OP had abandoned their pet cat somewhere it was likely to die.