How so?

The ships sunk in the Falklands War were all less than half the displacement of a typical US Navy destroyer. The sole exception is the Belgrano, which was built in the 1930s!

The ship being tested here is ~25x the size of the largest British ship that was sunk. Generally speaking, there is a super-linear relationship between ship size and the amount of explosive required to sink it. There is mountains of empirical data on this that you are choosing to ignore.

Every military knows this. They are making a tradeoff between size, which makes the target more difficult to destroy and easier to defend, and the number of ships they can build which allows them more flexibility in force projection.