What could the bigger pile of shit even possibly be?
His actual treason. They have gambled its better to take the hits for firing Comey than to allow Comey to continue his investigations. Comey announced he was working with the Eastern District in Virginia and Documents indicate the US Government convened a Grand Jury in that District in April for a case that's not being revealed.
If Comey was making progress it had to be stopped and they can effectively end it now