As Secretary of State, Hillary Clinton had no authority to disseminate IC information on her own, neither could she make it less highly classified (a process termed “downgrading” in the spy trade) without asking IC permission first.
It is a very big deal and less connected people who do this sort of thing ruin their lives, as any IC counterintelligence official can attest. During my NSA time, I saw junior personnel terminated for relatively minor infractions of security regulations. While the U.S. government unquestionably does over-classify items on the policy side, where almost everything in the Defense and State Departments gets some sort of classification stamp, not usually at a high level, intelligence reporting by its very nature is classified. If you don’t want the responsibility of a high-level government position, which inevitably brings with it TOP SECRET//SI access, then don’t accept that burden.
There’s still a lot we don’t know about Hillary’s Emailgate. Exactly how many emails contained TOPSECRET//SI information is unclear. We may never know since thousands of emails were already destroyed by Clinton. Who exactly placed the classified information in emails—it may not have been Hillary Clinton—and how did they access the information in the first place? How many of Hillary’s staffers at Foggy Bottom were also using her personal server?