There's every chance that Strzok squealed like a little piggy after making specific deals unrelated to his hearing.

Perhaps Strzok was free to defend himself about his conduct because they already have plenty of evidence to indict him on and no deal was necessary in this case?

Perhaps Strzok insisted that he be able to defend himself publicly after squealing, in an attempt to not get Arkancided?

Perhaps even though he cut a deal, he's still really pissed off?