Spook there are biblical references to how the deacons of the church should be admonished if they do wrong. we are to go to each other with love and in the spirit of kindness. We're not talking about booting folks out on their hiney literally. Folks who live those lifestyles are welcome to take a seat and listen to the preaching during any service. It's just not all inclusive membership. Here's an example that may help folks understand the WHY if I may...
Say a person who has several children out of wedlock, or is living with a paramour, or whatever...alot of those decisions are charachter flaws or lack of willingness to commit to any one woman/man etc. If a person is unwilling to commit to something as simple as having ONE spouse, how will they be commited with the church itself. How reliable will they be? It is screening for level of commitment and ability to commit in the first place.
There is no such thing as greater sin. Sin is sin. In the church we are supposed to hold each other accountable. We can't hold someone else accountable if we aren't setting good examples in the beginning.