[cm3]

My primary reason is that I don't view a page on the same display and machine as the author, so more often than not the presentation is sub-optimal or entirely unreadable locally. Custom fonts are similarly abused like low-contrast text (grey on white).

Also loading via JavaScript and changing the fonts of an already rendered page disrupts my reading. If you want remote fonts, load them from the beginning, or if this isn't possible, just don't, please.

Another justification for disabling remote fonts is that it's one security critical interpreter of complex data which, when disabled, doesn't adversely affect the presentation, whereas on most pages disabling images does and cannot reasonably be disabled. The latter justification may go away with Mozilla's Oxidation efforts with time, leaving just loading time and readability as arguments.