Racism, sexism, classism, even fatism were addressed. Gender issues too, including (EGADS!) what they nowadays call gender fluid issues - decades before social media made it cool.
One of the writers, she pushed for expanding women roles, and things like that third inter dude needed to procreate - that was her way of making that lady's fantasy a biological requirement, haha
A lot like Star Trek it was, with the parables. Also like Trek, above all was the bond between the characters. The show was about the alienation within us and the humanity that conquers that,,,
Ok, I'm sounding like a sap now,,,