It is impossible to be a 'homosexual' and a Christian. You cannot follow Christ and yet insist on living a sinful lifestyle
With respect, I believe that you can fall into the sin of homosexual conduct and be a believer. Ephesians 2:8 - "It is by grace you have been saved, through faith - not of yourselves, it is a gift from God." Our salvation isn't decided by our actions.
Now a Christian who falls into this sin will be desperate to repent and get help, and will be perfectly miserable until he/she does. These people need to be restored gently by the brethren.
But these people are pushing an un-Biblical agenda and passing it off as Christian teaching.