Isn't it nice that the gay community targets an amusement park designed specifically for children and families? (sarc)
As to why corporations aren't "supporting" them as much as the gay community would like, why should they? Why support 1-3% of the population and risk turning off the remaining 98%? Most consumers aren't gay. Those are the facts. Given the percentages, the gay community is actually overly represented in advertising, due to their well organized tactics and the fact that NY ad agencies and other creative mediums hire a higher than average percentage of the gay community.
Actually the reason for the overrepresentation is that they have a lot more disposable income per person than the average American, due to a combination of higher average education level and fewer children to support. Advertisers target people who can be persuaded to buy their products/services, not just random numbers of people. No point spending money to persuade people that they want your product/service, if they can't afford to buy it.