It's not the first fundraising site to crack down. GoFundMe announced a similar ban in late March. However, Indiegogo's move leaves anti-vaccination activists without another major source of income. This comes on top of another effort where Amazon pulled this latest documentary's predecessor from Prime Video after an outcry.

In all these cases, there's a consistent thread. Internet companies are increasingly aware of the potential role they play in spreading misinformation, and have decided that it's better to take a zero-tolerance policy on some issues than to be accused of contributing to real-world problems. And for vaccinations, the stakes are particularly high -- the last thing Indiegogo and others want is to be held responsible for an outbreak that leaves people seriously ill.