My family makes fun of me all the time but really, a fork does everything a spoon can do for ice cream, including being better at cutting it and being able to pick it up and lick it. Ice Cream is solid, I'm not eating it for the pure liquid goop.
Besides, what are you going to do when you make it towards the end and there's still some left in a small mound, + the melted 'cream? A spoon has a narrow end and it conforms to a bowl's shape so it's easier to scoop that up.
Ice cream is best eaten when it's hard. Therefore the sharpness of a fork can help when you just want a big gob of ice cream. Anyone who lets their ice cream last long enough where it becomes goop is a disgusting heathen.
But a fork is still wrong. Spoon 100% of the time.