You have read as many Morrissey interviews as I have over the years, and I have read just about every one he has ever done. The tone may change here and there but his tendency to exaggerate does not. It's not that he's "serious" in one place and "whimsical" in another. The point is that he overstates everything-- he seems almost pathologically incapable of uttering simple, unadorned declarative sentences. In particular he's always ratcheted up the verbal fireworks when talking about animal cruelty.
It was a dumb remark, but very much in line with his rhetorical style. Very little that Morrissey says is defensible on a strictly literal level, and that goes for every topic he's addressed, not just the controversial ones.