Maeda had a bunch of decent to good starts all the way into June last year. Once it became clear in July he didn't have it anymore, he was pushed to the bullpen to fill in with garbage time, basically out of harm's way. He got one more month this year to see whether he could turn it around. he couldn't and got let go. That seems pretty reasonable to me.
Shelby Miller went from July 1 to the end of last season with a 3.03 ERA, 3.67 FIP, only two blown saves, and a 24/6 K/BB ratio in his last 29+ innings. That doesn't sound ineffective to me.
Brebbia started out good this year, first nine appearances with a 1.00 ERA, 9/5 K/BB ratio, 3.67 FIP, no blown saves. He got hurt and then was given his chances to turn it around. After a month when it became apparent he'd lost it, he was released. That seems pretty reasonable.
In none of these cases does it seem to me that Harris irrationally kept running pitching out there hoping against hope he could save face on their signings while refusing to acknowledge they were failing. There must be some other guy you're thinking of that did that.