I quite enjoyed the movie but the two decades later District 9 dealt with this kind of problem in a much more believable way. While it's lovely to think of aliens living among us as equals, the District 9 scenario rang true.
Okay, you appear to have forgotten the hell out of Alien Nation
. While attempts were being made to integrate the Newcomers into American society, because that's what America aspires to at its best, the reality was that they were very, very far from being treated as equals, and the pervasive racism and intolerance they faced was a central thread of the series. The main recurring villains were Purists who wanted to exterminate them altogether, Final Solution style. Not to mention that they had originally been segregated in internment camps for a fair amount of time before being allowed to integrate.
And personally I think it's very believable that we'd be more willing to attempt integration with aliens who looked and sounded mostly human than we would with ones who looked like great big bugs. It's also very believable that 1990s America would be more willing to attempt integration than 1980s South Africa, before the end of apartheid, would've been. So I don't see any credibility gap between the two premises. They're similar thought experiments, but with different initial conditions, and thus different outcomes.