Well...maybe because in the two pages that we saw him, he was kind of a jerk....?
Not knowing his story is not an excuse for being a jerk. That's how in many other yaois we excuse the maltreatment or rape of the uke....because "we don't know his story yet..." (seme's)
I mean we've only read up to chapter two, I can't say i hate him yet because we haven't even gotten to know his story or really see what he's like.
P.S I REALLY HOPE THIS ENDS WITH A 3SOME BECAUSE I'M DOWN LMAO.