The fact is, Rosenstein (the current deputy director of the FBI!) wrote a report that the only way to restore public and internal confidence in the FBI was to fire Comey. I don't doubt that Comey's irresponsible acts made Trump consider the possibility of firing Comey before that. SO THE HELL WHAT?!? It was certainly not an unreasonable consideration. But it was on the recommendation of DOJ deputy director Rosenstein that Trump did so, for the good of the organization, not as part of any cover-up.
If you have a case for inaccuracy of that, feel free to make it.