Assuming you are really interested.

Mostly because the world is not one-dimensional.

"Hard lockdown" has drastic socio-economic implications.

"No lockdown" has dramatic/catastrophic socio-economic implications. The easiest to understand: In very short time the ICUs are overrun and people die. A lot of people die.

"Soft lockdown" depends on the people to play along. Which seems more difficult than the people in charge thought it would be (and some still don't believe).

Notably I am not arguing here for what the "right" choice is. It is simply not that easy.