It's not a question of evil or corrupt. The relevant words are careless and irresponsible. Colin Powell became SecState in 2001, and Clinton in 2009. Eight years is an eternity in the tech world. During that time government regulations and requirements changed substantially, and Clinton failed to comply with them. Powell's successor and Clinton's predecessor, Condoleezza Rice, was the most obvious person for Clinton to consult and emulate, and Rice did not use private email. And as Comey observed, even a Gmail account is protected from intrusion by Google's vast resources, while Clinton's basement server was protected -- if at all -- by one ex-campaign worker.
Once again, it's obvious that Clinton was evading federal record-keeping and Congressional access requirements, and her subsequent numerous, conflicting explanations are a smoke screen. Whether Powell or anybody else also did something wrong doesn't mitigate Clinton's misconduct.