Sure, a strong emphasis on the 'golden rule' is important, but it is not 'all-consuming' as far as Christianity is concerned. Each of the disciples were taught at jesus' feet and thus, they are apprised of his motivations and desires. Paul did not favorably meet Jesus during Jesus' earthly ministry, but he was none the less an apostle
After Paul met Jesus on the Damascus road, he went into town by following Jesus' directions..and was accepted by all the other apostles, even to the point where he was able to upbraid Peter and give him spiritual direction. The teachings of Paul are within keeping of Jesus' instructions, as evidenced by the apostles, complete backing of Paul and his teaching.
So now, perhaps as an able student of Biblical studies you can offer commentary on (Romans 1:22-29). Please, just a short synopsis will suffice...
"22 Claiming to be wise, they became utter fools instead. 23 And instead of worshiping the glorious, ever-living God, they worshiped idols made to look like mere people, or birds and animals and snakes. 24 So God let them go ahead and do whatever shameful things their hearts desired. As a result, they did vile and degrading things with each other's bodies. 25 Instead of believing what they knew was the truth about God, they deliberately chose to believe lies. So they worshiped the things God made but not the Creator himself, who is to be praised forever. Amen. 26 That is why God abandoned them to their shameful desires. Even the women turned against the natural way to have sex and instead indulged in sex with each other. 27 And the men, instead of having normal sexual relationships with women, burned with lust for each other. Men did shameful things with other men and, as a result, suffered within themselves the penalty they so richly deserved. 28 When they refused to acknowledge God, he abandoned them to their evil minds and let them do things that should never be done. 29 Their lives became full of every kind of wickedness, sin, greed, hate, envy, murder, fighting, deception, malicious behavior, and gossip." (Romans 1:22-29)