How is a law enforcement agent staring at some workstations and computers to know what equipment was involved in the alleged crime they are raiding the facility for?
That would be a valid argument if they timely returned whatever they don’t need, but they don’t, so it isn’t.
If the FBI was raiding a home for child abuse and pornography, there’s no way they have the access or expertise at the time of a raid to know the server in the corner is only for Mastodon, the box over there is just a Linux firewall, and that box over there is a porn server.
Maybe not, but if they’re not completely incompetent, they’ll have images of all of those devices within a day or two. They don’t have any legitimate need to keep the seized equipment after that.