For me, the alarming fact is that this "privacywise" option was not the firs one chosen. Instead, they went with a "privacyunwise" option as a default, and only backed out because of user uproar. Bad Mozilla!
Thanks for the replies, everyone. I have only used ImageMagick lightly, for e. g. resizing or merging simple bitmaps, and I never found it lacking. However, I recognize that there are users who need more.
So, a question: why? Just so that there is an alternative (not that there is anything wrong with that), or is there an issue with ImageMagick that discourages some people from using it?
Maybe it has to call home to microsoft to find out if the font is whitelisted? That would of course imply that in Windows 10, "disabled firewall" doesn't mean "all traffic allowed", which I find bizarre...