"Jesus never condemned homosexuality. So, why do you?"

Well, technically speaking Jesus said he did not come to condemn, but to give life. John said,

"For God sent not his Son into the world to condemn the world; but that the world through him might be saved." (John 3:17)

However, to say that Jesus did not address the homosexual issue, at least by inference, is simply not true.

Jesus said, [that] from the beginning of the creation God made them male and female. For this cause shall a man leave his father and mother, and cleave to his wife; And they twain shall be one flesh: so then they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder."  (Mark 10: 6-9)

This is in line with and in the broader context of the Genesis account and the proscriptions against homosexuality in both the Old and New Testament. To cleave to ones partner (as in marriage) and become one flesh through the sexual act, is what Jesus had in mind. The command to go forth and multiply is inclusive in the purpose of marriage and sexual partnerships; and is most surely something that homosexual partners can not do.