The decision to include a gay character was in an art form, not comparable to business matters. If all creators of art forms removed all elements of their work that could arouse controversy, the value of their work would be significantly reduced. While this business, on the other hand, does not lose anything by removing this controversy from their business matters; it prospers instead.
Also keep in mind that Disney is a much bigger corporation than the drive-in, meaning damages impact the drive-in more than Disney.