Question: At the end of the movie, we see the frozen blob dropped from an airplane over Antarctica using three large cargo parachutes, where hopefully it will remain frozen forever. My question is... If the goal was to destroy the blob, why did they bother wasting parachutes on it? Why not just kick it out of the plane and let it splat when it hits the ground?
Question: The movie was made in 1958, why does the calendar in police station show July 1957?
Answer: Because movies aren't always set in the year they're released. Absent any conflicting information, the assumption must be that the events of the movie take place around July 1957.
Answer: It could shatter into a million pieces. Even the most microscopic piece could float away to international waters, thaw out, and go on a rampage again. It needed to stay intact. Not one piece should get away. The Blob wasn't dead; it was frozen.