Re: "Code of Honor" Ligonians: Humans or Aliens?
Here are a couple of snippets from Mem Alpha regarding Frakes and Spiner's opinions.
Jonathan Frakes referred to the episode as a "racist piece of shit" . At a 2007 science fiction convention in Toronto, Canada, he told the audience, "The worst and most embarrassing and one that even Gene would have been embarrassed by was that horrible racist episode from the first season... Code of Honor, oh my God in heaven!" 
In a 2012 interview with TrekMovie.com, Brent Spiner recalled, "It ["Code of Honor"] was just a racist episode. Maybe not intentionally but it felt that way and looked that way. It was the third episode so it was fortuitous that we did our worst that early on and it never got quite that bad again." 
According to Wil Wheaton, 'if the cast wasn't arbitrarily decided to be African-American,' the idea of the episode being racist or non-racist wouldn't have been an issue. 
I would really love to hear the opinions of the people that played the Ligonians on the show. It would also really help to find some sort of review/reaction that was captured in 1987 to give some perspective of how it was received in that time period.
Searching for something, a million miles and a ways to go.