> We are completely fine growing so many pumpkins only for them to be carved and thrown away;

As far as entertainment goes, carving a pumpkin and then letting it quickly compost away is relatively low impact.

You could always argue that the most environmentally friendly option is to do nothing at all and cause nothing to be produced or moved around, but that's hardly a realistic argument. Criticizing every activity that causes something to be consumed, no matter how renewable or compostable, is hardly productive.

Once the environmental arguments get to the point where we're criticizing people for carving a vegetable up but not eating it once per year, it gets hard for people to take seriously.