If it was just gay people, they wouldn't bother. Gays aren't really a big enough demographic for a company as big as WotC to be worth pandering to. People who care about gay rights and want to affiliate themselves with 'progressive' companies, however (and people who will stop buying from companies they think are 'problematic') are a massive block that are both quite unified and easy to cater to. Particularly among the younger age-ranges with enough disposable income to spend on this sort of thing. So it's just sensible business to pander to their political beliefs.
The fact that a soulless corporation like this is pandering to progressives means that they think the progressives represent their biggest potential market. If the reactionaries were their best market, they'd be who WotC panders to, but they're not: they're insignificant enough that WotC know they can afford to push them out and - not only will those lost sales have a real effect on their bottom line - but doing so will only cement their hold on the larger demographics that they want to cater to.
If you think this is driven by anything other than WotC going where the money is, you're a fool. This is what capitalism does to culture.