Your complaint is not ignored, but the financial/legal folks say this is necessary. Thank you for your donation. You're one of the minority that helps keep Thunderbird available to everyone.

from the FAQ on https://www.thunderbird.net/donate/#faq

Why do you need my address in order to process a gift? We understand that your privacy is very important. We ask for a minimum amount of information required to process credit card payments, including billing addresses. This allows our payment processor to verify your identity, process your payment, and prevent fraudulent charges to your credit card. We keep your information private — if you have questions, please refer to our Privacy Policy. If you would rather not fill in your information on our online form, you can mail us a cheque.