It's because WF is a sacrificial lamb. These issues at WF have been known for years by the regulators, the banks, and others (the general public just found out about it with the fine that was big news, but it wasn't a secret by any stretch). The 5300 people weren't all fired that week, and many of the customers who had been financially impacted had already had fees returned to them before it hit the news. Hell, it wasn't even the regulators who found the issue in the bank years ago, it was supposedly Wells Fargo itself. The LA Times also supposedly unearthed it in 2013.

This is election year posturing. All the big banks have similar issues (WF is not some sort of lone wolf) and aren't getting torn apart similarly.

In reality the banks probably should all be broken up, but that's not going to happen either. Instead it's going to lead to more half baked regulation, more tv time for people who are looking to benefit politically, and actually lead to more jobs at the banks (gotta get those new regulations and additional scrutiny under control internally).