I always love companies explaining their decisions as if they had some kind of moral high ground and it's their duty for the good of the people.
The real reason is summed up perfectly in the article: "a substantial portion of our community (including donors and campaigns) have been motivated by opposition to Donald Trump".
It's all about the money, all the time so the company should stop treating the readers as if they are 3 year old while spinning a moral story of Prince Charming battling the Big Bad Evil.
Let's not get started in with "Though we are an open and non-partisan platform...". That phrase went goodbye forever when this decision was made. They chose a side and now they have to live up with the decision.
What irks me is that has happened since ever and companies sway with public opinions as reeds in the wind: pro-war (Vietnam, Irak, Afghanistan etc.) then anti-war, anti-black, anti-jew, anti-woman and anti-lgbt (yeah companies used to discriminate and spun a moral fairy tale to justify their decisions). Now companies are saying that discrimination is bad except when it's against republicans. I hope the irony is not lost on them.
Wow, that's a really difficult position to be in. It's understandable that you don't want to be a fundraising platform for racists and nazis, but I think its going to be incredible difficult to separate republicans into categories. I look forward to seeing how it works out. My guess is that you'll just end up becoming a non-republican political fundraising group.