I think what that quote really means is that when you are young, and have very little property and power, you are more likely to be vocal in saying what you think OTHER people should do with their money and power, a typically liberal position.
When you older and have accrued property and power, you are more likely to be vocal in saying that OTHER people shouldn’t be telling you what to do with your money and power, a typically conservative position.
It doesn’t literally have anything to do with your heart (kindness) or brain (intellect)