For with what judgment ye judge, ye shall be judged: and with what measure ye mete, it shall be measured to you again.
This is a warning against hypocrisy. It is possible to judge rightly. We are called to discern good from evil and act accordingly.
Hebrews 5:14
But solid food is for the mature, who by constant use have trained themselves to distinguish good from evil.
The bible condemns fornication constantly when speaking about fleshly evil. And since there is no scripture in the bible condoning homosexual marriage, the act is always considered fornication by the bible. Homosexuality is considered an abomination in the OT and is condemned as sexual immorality in the NT.
1 Corinthians 6:9
Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived: neither the sexually immoral, nor idolaters, nor adulterers, nor men who practice homosexuality
So if you are involved in a same-sex relationship, I'd just caution you to really pray about it and read scripture closely and ask God to reveal that truth to you. It may be difficult, but when we are called to give up sin in our lives to follow the Lord more closely it is always worth it.