I'm not that sure about the theme myself. If this were a funny poem, I could go with the concept, but a serious(ly unneeded) defense of short men somehow rubs the wrong way, in my opinion, with its implicit suggestion that short men need defending, and its further suggestion that short men generally share the listed virtues that are perhaps less common in men of taller stature. Ultimately, I suppose, the poem is a criticism of
all men
except the short ones, suggesting that taller men lack wit and humor, look for fights, cut others down, and lack empathy. The premise is ridiculous as a factual matter (i.e., not even slightly accurate or insightful), and at least mildly offensive. Stereotyping is stereotyping, whether it's by race and gender (which we all know is wrong) or some other physical characteristic that has nothing to do with character or personality.
This made me think of Randy Newman's "
Short People" song, which is rather brilliant in my opinion (I'm six feet tall) but I've heard at least some short people are not as amused. It's successful, though, because it's so obviously meant as a humorous way of making fun of prejudice, not participating in prejudice. Your poem though, seems to be expressing sincere views without irony.
I agree with Julie about "ken" and "wren," both of which struck me as forced for the rhyme. But on the whole, the poem is well made even if I'm finding what it says to be offputting.