I think you need to make a distinction between the different types of laws in the Old Testament and why they existed. Once you do, you will realize that there is a big difference between a judicial law (such as the command not to eat pork) and a moral law.

All laws in the OT fall into one of three categories. Judicial laws, Ceremonial laws, and Moral laws. Of these three categories, only one, the moral laws, remains relevant today.

When God gave the Israelites the laws of the OT, he was guiding them in the creation of a new nation. The Israelites had never been an independent nation before and needed a system of government and a judicial system to maintain order in their new society. God, in his infinite wisdom, helped them by providing a number of judicial laws. These laws covered everything from how to conduct law suits to what the sanitation standards should be. Because we are no longer living in that nation, there is no reason to follow those laws. Those laws were written for a specific people in a specific time in order to help them establish their nation; we are not those people and are not living in those times. The command against eating pork was most likely, just as you claim, based on sanitation and we no longer need to follow it; not because it is no longer a good idea to avoid pork (it actually is a good idea to avoid it for health reasons), but because we aren't living in ancient Israel.

The second type of laws we find throughout the old testament are ceremonial laws. These laws existed in order to remind the Jewish people of certain aspects of God's nature or their own divine purpose; or to show the Jewish people what it takes to be holy if you want to do it on your own. These laws included all the laws on sacrifice as well as commands against wearing clothing made of more than one fabric, and similar ceremonial concerns. We no longer need to follow these laws because when Jesus died on the cross, he fulfilled the law and rendered all these ceremonies obsolete. No longer do we have to go through a system of ritual cleansing and sacrifice in order to approach the altar on just one day of the year. Now we can each go directly to God ourselves. In fulfilling the law and the prophecies, Jesus rendered the ceremonial components obsolete. Jesus established only one ceremony, the breaking of bread in remembrance of him.

The final type of laws we run into in the OT are the moral laws. This is where God laid down his rules about what is right and wrong. This is where he revealed the moral absolutes that exist in the universe. These laws are the foundation of what is right and wrong and they do not change. These laws we are expected to follow today.

So, where does homosexuality fit in? You can still attempt to argue that the laws against homosexuality are judicial laws meant to separate them from the pagans who practiced such things in the region. But personally, I believe these are moral laws that are absolute. While we no longer live in Israel and thus shouldn't apply the punishments recommended in the OT, the fact it is wrong remains so to this day.