Yes ice cream is good for when you have a sore throat.
The ice cream is easy for you to get down your throat when it's sore and the ice cream can also help soothe your sore throat as well.
The coolness of the ice cream can help your sore throat and even drinking some cold milkshakes can help with the sore throat.
I would also recommend eating some chicken noodle soup as the chicken noodle soup ensures you get some food inside you as well and the chicken noodle soup helps fight the cold and flu virus as well.
When I have a cold or flu virus and sore throat all I can really eat is some apple sauce, chicken noodle soup or some ice cream.
Then within a few days to a week or so the sore throat and cold or flu virus should go away.