Why do caged birds say, "Alas! Your fate is the same as mine now.

Mainly refers to the fetters of the people's country.

Caged birds are kept in cages and can't see the outside world. Nowadays, most people will be fettered by foreign objects, and they don't feel as free as they did when they were children.

Modern people are constrained by houses and cars, so they are always timid in doing things.