Perhaps you have heard about the shocking experiments of Martin Seligman in 1967. Back then he electrocuted poor puppies, observed their reaction, and came out with the term in the title.
What you might not know is that 50 years later, he published a sequel, in which he redefined 'learned helplessness' based on findings from neuroscience. Turned out there is nothing learned about helplessness. On the contrary, you have to learn to stop being helpless.
Here's a quote:
In conclusion, the neural circuitry underlying the phenomenon of learned helplessness strongly suggests that helplessness was not learned in the original experiments. Rather passivity and heightened anxiety are the default mammalian reaction to prolonged bad events. What can be learned is cortical—that bad events will be controllable in the future.
So helplessness (or freeze) is the default behaviour in mammals. To trigger fight-or-flight response you have to learn.
This is how science work