While I wouldn't have stopped this myself, I think its perfectly reasonable for a crowdfunding website to not want to host campaigns used to purchase military grade weaponry.
That's fine, and they're within their rights to have this policy in place, but it doesn't change the fact that they've completely fucked over the volunteers in their hour of need.
"It's a violation of our policies" doesn't magically clear their conscience. It's just another way of saying "because we can".
Companies do this all the time and I have no idea why we accept it.
Because a private company is perfectly entitled to NOT want their platform to be used to fund weapons. That isn't unusual and it absolutely IS perfectly acceptable.
What's the alternative exactly? Propose legislation to force websites to allow arms sales? Give me a break.