It's feasible that Whaley is frustrated that a unit that is Rex's responsibility, with everything Rex wanted/needed, with much of their offseason resources dedicated to it, is still crappy.
I mean, if Rex said, get me LorAx, ZB, Ragland, Wahsington, and Lawson and our unit will be great, and screwed it all up which potentially jeopardized your job, I'd be pissed.