the gnupg software
the website/app holders are asking for donation to download the software
Yes, you're correct. If you use that particular link, they are indeed requesting a donation. It also appears there's a $0 option there as well, but I did not investigate it.
That said, if you use the download link that the tutorial directs you to, you can download that software without a donation request.
Edit: Per the tutorial, use the
link that the red arrow is pointing to ...