Why do many Christians believe Old Testament laws (like dietary restrictions and ritual purity) no longer apply, but still hold that homosexuality is sinful?

I’ve been reading the Bible and had a question about how Old Testament laws are applied in Christianity. In the time of Moses, the Israelites had many laws they had to follow—things like avoiding certain foods, staying away from dead bodies, and being considered “unclean” for various reasons (e.g., a woman’s period). However, most Christians today believe that these laws are no longer necessary because Jesus’ death fulfilled the law, making these regulations obsolete (Matthew 5:17, Galatians 3:23-25).

Yet, when it comes to homosexuality, which is also condemned in Leviticus (18:22, 20:13), many Christians still believe it is a sin. If laws about food, ritual purity, and other cultural practices no longer apply, why is homosexuality often treated differently?

I understand that some argue there’s a distinction between moral law (which still applies) and ceremonial/civil law (which was fulfilled by Jesus). But where is that distinction explicitly made in Scripture? And if Jesus declared all foods clean (Mark 7:19) and lifted purity laws (Acts 10:9-16), why wouldn’t the same reasoning apply to Leviticus’ statements on homosexuality?

Additionally, are there any historical or cultural factors that might explain why some Old Testament laws were set aside while others were reaffirmed? And how do different Christian traditions interpret this issue?

I’m not looking to start a debate—just genuinely curious about the theological reasoning behind this. Thanks in advance for any insights!