Even in 1970 that could not have made sense to anybody with a brain. They certainly knew enough about explosives to know that the kind of blast required to reliably vaporize an entire whale carcass would be considerably larger than anything they were going to do on a public beach. That whole event was just a couple dudes who thought it would be hilarious and insufficient supervision by adults.

Diluting salty rotting fish sauce in seawater is a lot more defensible. It's not like they'd have to just dump it all in one spot.