Gasperini took over the Inter job last week and has brought along Ivan Juric as his assistant manager, removing him as Coach of the Genoa youth team.
"I am really annoyed about this situation, because it involves a club that I did have a good rapport with," declared Preziosi on Telenord.
"I won't say that rapport is compromised, but what happened is pretty negative. I'm upset at Juric's departure. The fault does not lie with Inter or Massimo Moratti, as I put the blame squarely on Gasperini.
"I helped him to get the Inter job and this is how he repaid me, by calling Juric to San Siro.
"I have to say Gasperini's behaviour did not surprise me, but I won't forget it either. I am very upset and bitter about this."
Preziosi also maintained Gasperini tried to bring several other members of his old staff to Inter.
"At least they turned him down, but Gasperini insulted them when he was rejected. It's only right that I saw certain things so you understand who we're dealing with.
"Genoa have proved we can do without him. I am accustomed to defending my former colleagues and even worked to help some get new jobs."