The first film only had a black mayor (who used to be a cleaner) and a group of black musicians (who smoke weed out back during the break). Their entire purpose, for the most part, is to serve as the butt of several jokes (e.g. the cleaner being overly excited that he's going to become the mayor in the future, the musicians scaring the ruffians by outnumbering them) and Marty directly gets credit for the achievements of at least two black men (the cleaner getting the idea and confidence to enter politics and run for mayor, one of the black musicians calling Chuck Berry, giving him the idea for Johnny B Goode when Marty is performing).

Martys girlfriend is left out of the majority of the first film's plot, spends the majority of the second's film knocked out (both initially and again later) -- pretty much only serving as an excuse to distract Marty and Emmet long enough that bad things can happen, and then only returns at the very end of the third film.

The only strong female character is the teacher in the third film, whose first appearance is literally as a damsel in distress and who again ends up in distress during the film's climax (so Emmet can save her). Heck, a lot of the plot of all three movies is built around saving damsels in distress.

Don't get me wrong. Personally I think the three films make an awesome trilogy and I understand why they have become the pop culture icon they are, but they make incredibly easy targets if you want to call out racist/sexist stereotypes in popular media.

I find that forcing myself not to use such words means I have to actually express why I don't like something, which is a nice side bonus.