This is the sort of mis-use of logic that has led to so many problems.
"Lockdowns" is shorthand for "people not coming into contact with other people in a way that spreads the virus"
It's shorthand for a set of government policies that were intended to reduce contact, not eliminate it, because "not coming into contact with other people" is impossible. People still have to go to shops, hospitals, care homes, live with each other, travel around and so on even during a lockdown.
Your belief that it's "completely absurd" to say lockdowns don't affect mortality is based on the kind of abstract but false reasoning that consistently leads epidemiologists astray. Consider a simple scenario in which lockdowns have no effect that's still compatible with germ theory - you're exposed to the virus normally 10 times per week every week. With lockdowns that drops to 5 times a week. It doesn't matter. Everyone is still exposed frequently enough that there will be no difference in outcomes.
"Because the virus cannot teleport through walls, lockdowns necessarily prevent transmission"
https://www.washingtonpost.com/archive/politics/2003/04/18/i...
Viruses can in fact teleport through walls: "The SARS virus that infected hundreds of people in a 33-story Hong Kong apartment tower probably spread in part by traveling through bathroom drainpipes, officials said yesterday in what would be a disturbing new confirmation of the microbe's versatility."