Because agents were loyal to Comey. They proved it by wearing pro-Comey T-shirts to an outdoor FBI party a few months after the firing. If Trump wanted to ratchet the hard feelings against him up to an ouright rebellion, he’d have fired McCabe also.
And before you start bragging about how you’d have fired McCabe anyway, A, you have no idea of the breadth and depth of the resistance Trump is facing, and B, McConnell could have done more to expedite the Wray confirmation, which will resolve the McCabe issue without further anti-Trump blowback.
Time for a special counsel to investigate Mueller’s ties to Comey and their obvious Paki connections through the DNC. Put the pressure where it belongs, dig up Mueller’s connections and finances and that of his whole team.
I have spent many years in government so I have some idea of what he faces. It will take a backbone of steel to do what is necessary. He has started in some respects, not so much in others. The only complaint I have is some of his policies are not conservative enough but he is light years ahead of Hillary or any other Democrat.