I'd say only to Trump fans that really don't care because they'd have thought it a genius move no matter what he did including having him called to the White House and publicly executed on the front lawn.
The issue with Trump's claim is that at the time Trump was acting as Comey's cheerleader. You don't get to cheer on someone and then six months later declare that the very thing you cheered on was a firing offence. If it's a firing offence now, then it was 6 months ago too when you were all for it. What that reeks of is hypocrisy.
There is also the matter that the actions aren't Trump's concern as a boss. They were dealt with under Comey's boss at the time, Obama. If it was a fireable offence, then he should have been fired then. If you don't get why then look at it this way. You do something in your job that breeches the rules. Your boss considers it and lets you off with a warning. Six months later a new boss comes in and decides that the warning was insufficient and fires you for something that you didn't even do on his watch and had been actioned already. See why such a thing is unfair?
What else do we let this sort of thing happen for? If a new moderator doesn't like how one of your posts was handled six months ago, should they be allowed to have you banned over it? In a new Prosecutor decides that he didn't like that you were warned rather than prosecuted for something, should he be able to restart legal actions against you after they were dealt with?
If this sort of thing is allowable and fine, then no one is ever safe from further retaliation over their actions because anyone can later revise the issue and take further actions against you. This is a totally unjustifiable and unfair way to live, and why such things as double jeopardy laws were included in our criminal justice systems.
Now in all of this, I'm not disagreeing with Trump firing Comey, he has that right, though it is rarely used, but what I am saying is that it's not a Genius move to blame it on the way that he handled the Clinton Email Case since at the time Trump was his biggest cheer-leader and so now in claiming to be firing him for it, Trump is behaving hypocritically.