I’d also note that Inventory keeps historical data to report your computer and software license usage over time. As we could report on you license usage for a period in the past, it is necessary to keep computers after they have been decommissioned (and license info for applications that have since been removed).
What API call are you using, and what do you want it to reflect? All computers that have existed, or a specific point in time,.or only the current state?
I would expect to use the valid_from and valid_to fields in that case