Gentile morality

Quoted in the Talmud (22:10)
"Rabbin Gamaliel answered and said, "The righteousness of a nation exalted is Israel, as it is written, and who is like your people Israel? And kindness to the nations is a sin. Every righteousness and kindness that the Gentiles do is a sin to them, and they do nothing but boast about it. And everyone who boasts falls into Gehenna, as it is said (Proverbs 21:24). This is the arrogant, deceitful man who commits a wicked transgression, and there is no transgression but Gehenna, as it is said (Zephaniah 1:15). The day of his transgression, that day is."
How do you understand this gemara? Is there an argument here that everything that the Gentiles do stems from an egoistic perception, meaning that there are essentially no moral Gentiles? And what do you think about the relevance of this gemara today?