It will come as no surprise to the reader that Upotte objectifies girls. That is, after all, literally the premise of the show: that girls can actually be guns. But perhaps the truly artistic element of its premise is that statement in reverse: that guns – inanimate objects – can be girly.
Perhaps the teacher’s dilemma is that these guns cannot be treated as such – they have feelings of shyness and inadequacy, and are embarrassed easily, just like ordinary girls. Rather than showing the girls responding well to being treated like guns, the lesson of Upotte seems to be the backwards implication that guns ought to be treated more like girls: given leeway for their unique personality quirks, handled with care and delicacy, and generally treated with respect.