I remember watching a program on whales in the 1980s involving a group of
anti-whaling activists trying to stopa much larger whaling vessel from killing
a group of sperm whales (in terms of mass, they have the largest brains on
Earth).

Though the speed boat of the AWAs tried to get in-between the harpooner
and a whale, the harpooner succeeding in hitting and eventually killing a
female sperm whale. Her mate went charging at the whaling boat and tried
to actually get at the harpooner. The harpooner just reloaded another
harpoon and killed the male sperm whale.

One of the AWAs said that what got him was how the male sperm whale
in its rush to defend its mate actually swam by the small AWA boat and
looked right at its crew, then kept going for the large whaling vessel.
A more base animal would have presumably just attacked whatever
was in its way and looked like a threat.

So even though whales haven't developed some kind of personal
body armor or their own attack submarine (okay, now there's an
intriuging SF plot), they don't just roll over and die when attacked
by humans.

One scientist even said that when whales probably first looked at
humans, they compared body sizes and figured these little creatures
wouldn't be much of a threat. Perhaps the whale simply hasn't had
time to evolve to take sufficient action against human ambition and
technology.

And think of this: Humans have put in a lot of resources and time
to hunt down whales by the many thousands. It wasn't just a
couple of guys with a spear or two chasing after a whale or two.
Any animal would be smart enough to avoid that. Humans made
an entire industry to go after creatures who had spent most of
their 30 million years on this planet pretty much being left alone
due to their bulk and their environment. The occassional orca
attack is nothing compared to what humans amassed on those
creatures of the deep.