Collin Powell did not go down to Radio Shack and purchase a server.
Collin Powell did not claim said server was secure because two secret service agents were guarding it.
Collin Powell did not claim e-mails were unclassified because they were not marked as such.
Collin Powell did not lie to Congress about the presence of classified documents on a personal server.
etc. etc. etc.

If he did what Hillary did, then yes, he should be incarcerated as she should be.