It's a little outside of my lane, but thank you very much for the question.
I'm not an expert on the service providers or GoFundMe, but my understanding is that the page is set up for a particular cause. When people want to donate, a behind-the-scenes service is provided. Stripe, for example, would have the identity of the person making the donation. They would have their credit card and all their identification in order to validate that the funds exist and transfer them to the particular page. They would know that it's going to a particular page.
My understanding is that Stripe, PayPal, GoFundMe and GiveSendGo all have terms of service where they clearly identify that they will not support anything that is related to money laundering, criminal activity or terrorist financing.
I would assume that many of these—given that they exist, as in the example of Stripe, in a million different companies and hundreds of countries—do have their own internal compliance program and their own internal media watch program. I would assume they are very socially responsible when it comes to identifying where that money may be going. I would think they would not want to process money that was going to a cause that was identified as illegal, for example.