It’s interesting that when some condemn Leviticus for being backwards, they ignore the good that is in there. I don’t think the site you reference would mention:
Do not curse the deaf or put a stumbling block in front of the blind, but fear your God. I am the Lord.(Lev 19:14)
The Levitical dietary laws - which aren’t directly mentioned below:
biblebabble.curbjaw.com/laws.htm
are contravened by Divine command in Acts 11. Paul extends this line of thought further in Romans 14. In general, though, the laws under the Mosaic Covenant that were manifestations of Divine Will specific to the Covenant are discontinued under the New Covenant, even if the substance of the law remains. For example, the condemnation of sexual immorality (of which homosexuality is a small part in terms of total text as well as how often its practiced) remains from the beginning, even though the Mosaic Covenant called for execution while the New Covenant calls for separation from the Church.
As for specific reasons why certain laws aren’t followed, I think there are three overarching themes you can use:
- Separation as a form of holiness
- The demand for blood sacrifice is satisfied
- Scientific reasons for certain laws
We don’t follow the first because the reason for the separation is either no longer evident (the prohibition against eating a calf boiled in its mothers’ milk was a pagan rite that is no longer recognized today - no one thinks eating a cheeseburger is worshipping Ishtar), or because Christ has set us apart by His Sacrifice.
We don’t follow the second because the need for blood is satiated by Christ (Heb 9:14). To be fair, the Jews who still uphold the Mosaic Covenant no longer participate in blood sacrifice as commanded in Leviticus because the Temple is destroyed.
The third reason probably wouldn’t be bad to follow - and where we do it’s probably without realizing it. Laws like this are that new fruit trees should not be harvested for the first three years (ensure viability of food supply), and no sex during menstruation (supposedly there’s evidence that such acts lead to a higher risk of ectopic pregnancy).
But why aren’t we under the Mosaic Covenant? Jesus.