Yeah but it makes sense thinking about it.
Romm sees and hears the ghosts he can empathize with them to some extent, letting them roam longer is a thing but they might lose their minds and turn bad.
Romm let's "OK" ghosts roam in our plane longer as long as they aren't dangerous yet
Sato can't diagnose or empathize with the ghosts, so he remove them because he can't just play hide and seek with them if they turn bad later.
I believe Sato can be "bargained with", if Miko promises to keep her dad and his pet ghost in check
You are actually so right...
It makes me sad too
THAT'S WHY ROMM DOESN'T LIKE HOW SATO-SAN' WORK! HE'S ERASED EVERY GHOST EVEN IF THE GHOST IS 'KIND GHOST' LIKE MIKO'S FATHER PLEASE SATO-SAN YOU CAN ERASE THE OLDMAN GHOST, NOT THE FATHER AND HIS HORSE