I agree that icon fonts are a hack, but the web is made of countless hacks. This specific one seems benign. Users won't notice or care whether you use icon fonts or images. Icon fonts are approximately the size of the equivalent images, they work alright across platforms, and they're pretty easy to use and deploy.
It's not benign -- icon fonts are bad for accessibility because screen readers will read out the actual glyph unless you use pseudo-elements or extra markup. Additionally, many users on limited connections will turn off web fonts, and then your icons will break.
It's a hack that was necessary at one point, but has been largely displaced, like table layouts or image-based drop-shadows. SVG is just better nowadays[0]. You can even use the same pseudo-element tricks to insert them purely in CSS, which is yet another accessibility win.
Maybe I'm mistaken, but f I recall correctly, I think the issue with icons as font was accessibility, rather the average user with full sensory capabilities.
