Here's allmusic:
Perhaps Sly & the Family Stone's most universal message, "Everyday People" is sort of Sly Stone's own "All You Need Is Love." A simple, direct comment on discrimination, the literate and concise words come through to any listener, whatever their creed or color. Musically, the song is built around an almost nursery rhyme melody and rhythm, and this suggests that perhaps Sly had the lyric idea at the outset of the creation and attempted (successfully) to make the overall song as accessible as possible.
And from the wiki blurb:
The song is one of Sly Stone's pleas for peace and equality between differing races and social groups, a major theme and focus for the band. The Family Stone featured Caucasians Greg Errico and Jerry Martini in its lineup, as well as females Rose Stone and Cynthia Robinson; making it the first major integrated band in rock history. Sly & the Family Stone's message was about peace and equality through music, and this song reflects the same.
Sly's sister Rose Stone sings bridging sections that mock the futility of people hating each other for being tall, short, fat, skinny, white, black, or anything else. The bridges of the song contain the line "different strokes for different folks," which became a popular catchphrase in 1969.