Q: Why didn’t Jesus say anything against homosexuality? Was it because the Hebrew Scriptures were so clear about it that he didn’t feel the need to say more; did he just assume everyone thought homosexuality was wrong and his silence was basically agreement?
A: Let’s consider what the scriptures available to Jesus had to say about homosexuality.
Many people assume the story of Sodom & Gomorrah condemns homosexuality, but it doesn’t.
The prophet Ezekiel stated the sin of Sodom was inhospitality and lack of compassion and lack of concern for the poor (the Sodom & Gomorrah story includes attempted gang rape and repeated incest; there is not a single mention of same-gender love or mutual attraction...in fact, the story concludes by showing that the Moabites and Ammonites were the product of incest...the story is an ethnic slur against enemies, not a prohibition against gays).
Some will say that the Adam and Eve story where the man is told to “cleave unto his wife and become one flesh” is a statement against same-sex marriage. But the creation myths are just that...origin myths, not dictates about marriage (in fact, the Hebrew word "woman" has too often been mistranslated as "wife" but there is no ritual marriage in the story).
That leaves only two verses in Leviticus from the Hebrew texts that could be considered "homophobic". Two verses....not two stories, not two chapters, just two sentences.
Since Jesus reinterpreted, ignored, or defied ancient texts that called for killing Canaanites (he healed the Canaanite woman's daughter) or keeping a strict Sabbath (saying the Sabbath was made for us, not us for the Sabbath), or killing those caught in adultery (he rescued a woman who was about to be stoned, noticing, no doubt, that her co-adulterer somehow had escaped punishment), there is no reason to believe that Jesus would have been one to enforce two obscure and isolated verses from one book of the Torah. So, from the evidence that I can gather, I believe Jesus didn't mention homosexuality because it wasn't an issue of concern for him.
Secondarily, we know from history that eunuchs were "functionally" homosexual (that is, as slaves, they were often used for male/male sex), and Jesus in Matthew's gospel advocates for eunuchs, and (in his Jesus like way) even broadened the definition of eunuch to include those who are born sexually different.
There is another story of Jesus healing a centurion’s "servant" and the Greek word used for servant was often used to refer to a sex-slave (and a sexual relationship would explain why a Roman nobleman would seek out a Jewish healer to help his "servant"...only romance would explain the desperation of seeking out a peasant magician to help save someone).
So, not only did Jesus never condemn homosexuality (and his scriptures only mention homosexuality negatively twice and he never referenced those writings), but there are times when he seems to have embraced same-gender loving people. That proves nothing about the rightness or wrongness of same-gender love and attraction, but it does suggest that condemning it in Jesus' name is myopic and ahistoric.