He was a true Pope, who wandered off into heresy.
Just as Augustine was a true Church Father who also wandered off into heresy. Origen might have been recognized as such if he had rejected and recanted his heresies. Augustine did and rightfully takes his place as a giant of the Church.
By your argument Augustine was restored as a "Church Father" (another fictional/nonexistant list) because he "recanted and rejected his heresies".
Honorius was convicted of the heresy of teaching Monothelitism, a matter of faith and morals. The pope is speaking "infallibly" when speaking on a matter of faith and morals. Was Honorius speaking infallibly on a mater which he never recanted or was he not a Pope?