They're not asking you to make a donation. They want you to help them get an online federal form fixed:
I'm a US citizen who has lived in Canada the past 8 years. This year, my husband and I (also a US citizen) decided to move back to the US and live in Minneapolis with our 2 amazing kids. Because our boys are Canadian citizens, we went through the process of applying for US visas, which have been approved. But they are unable to move to the US because an online form called the DS-260 is broken. This form is the last step in the visa process. My family and I are being kept apart solely due to a technical glitch. There is no timeline when the system will be working again. Please email your senator or congressperson to fix the online immigration form called the DS 260. It's broken, and until it's fixed, I can't see my husband or two boys. If you don't know your representative, you can go to www.house.gov or www.senate.gov.
This broken form is doubtless screwing up the visa process for straight families, too.