Well, just that one episode never made it to air nationally (Drtooth swore WGBH in Boston aired it once). But in this case, I feel like the backlash would have been on a much larger scale, considering Francine is a major character in the franchise.
But interestingly, a lot of fans have been wanting the show to introduce a LGBT character for quite some time now . . . then again, they've also been wanting a goth character, an emo character, and all kinds of characters you can imagine would be controversial for a kids show to include.