There was plenty of backlash by conservative groups in the 90s and 2000s. Companies that offered domestic partner policies to their employees were targeted, along with companies that held special events for gays or were perceived to do so. Disney was an early adopter of domestic partner benefits, owned the channel Ellen was on (ABC), and had Gay Days at Disney World (though it wasn't officially sponsored). The Southern Baptist Convention voted to boycott Disney over these things.

I know that's not an ad campaign, but it's worth mentioning. Ads targeting the LGB at the time were largely restricted to gay publications like The Advocate.