It is not that it “justifies” or is an “example” of a successful same-sex relationship/partnership. (Which isn’t the case because they did eventually part ways. Later on Johnathan died in battle.)
It is the fact that David and Johnathan were able to enter in a union of that nature and still have God’s favor. Not God’s judgement. God still loved them both. No matter whom they loved or were in love with.
In fact David became King; to rule over Judah. The land of God’s people. (Yes, he had his sins. I have yet to find a ruler in that period whom didn’t have their black marks.)
The Idea they fear is the fact that King David, who was indeed favored by God, was not punished or cased out of God’s favor for his relationship with Johnathan. God still loved him and gave King David many blessings throughout his life.
Basically stating that homosexuality is not a sin to begin with. Which contradicts what the hate-mongering church leaders are spewing to the masses from their pulpits on high. Acting as though they are better then those they serve. (Which is actually a sin within itself.)
Thankfully not all Christians, myself included, fallow these bigoted teachings blindly.
One day I hope things will change for the better. That love will be seen as love. Not something that should be vilified.