You should teach law at Columbia! Your quick google search would probably have persuaded Comey and his lawyerin buddy that Comey was putting himself in real legal jeopardy.
The point that you are missing (I guess you didn't watch Comey's testimony?) was that the firing changed the meaning of Trump's comments from Trump being a bumbling noob to someone who was trying to influence how Comey proceeded in the Russia investigation, and when he couldn't and saw the investigation heading in a direction Trump didn't like, he fired him. Then the administration cooked up some phony reasons for his firing, that Trump contradicted in his Lester Holt interview, and also in his meeting with the Russians saying Comey's firing relieved great pressure.
As for him being a "leaker and snake," I will take the previous, and 2 subsequent, FBI directors opinions about Comey, along with everyone else who isn't Trump, or isn't being paid by Trump. I mean, have you ever once considered that Trump is just a lying sack of shit?