Would it be correct to say -
“Why are you heating ice-cream on the stove. It beats the whole idea/purpose of serving cold.”
The phrase is ‘defeat the purpose’. This means it is counterproductive or it is not directed toward the stated goal.
Thanks 
Would it be correct to say -
“Why are you heating ice-cream on the stove. It beats the whole idea/purpose of serving cold.”
The phrase is ‘defeat the purpose’. This means it is counterproductive or it is not directed toward the stated goal.
Thanks