Then you run into someone like me whose eyes are not as young as they once were, and who doesn't care to be abused with whatever happens to be the stylish designer's font palette du jour, and who therefore uses his browser settings to apply a minimum font size and a set of preferred typefaces which page styles aren't allowed to override, and then everything goes to hell.
Can you argue that it's my fault, not yours, that your page doesn't render well under the requirements I impose on the web content I consume? Sure, you can so argue. But every time you have to make that argument with a user, even if you win the argument in that instance, you're still both limiting your potential user base and risking a perception that you're less concerned with your users' needs than with satisfying your own desires.
I'm going to go out on a limb and suggest that if you're applying font size minimums and enforcing certain typefaces, you're probably fairly use to a web experience that isn't as the web developer / designer intended. I don't know anyone who QA's their designs with different browser font sizes.
I do; it's not very hard to build a layout which looks like what the designer intended for those who don't enforce font sizes or faces, and which also behaves gracefully for those who do (e.g., no text spilling out of its containers, &c.) You might be surprised how little effort that takes, and I think the result is much better for it.
Well, that minimum font size wouldn't apply to SVG icons, so you're still not going to see them very well. So, it may be more effective to zoom the entire page overall rather than just font sizes.
Also, note that you apparently don't assign any culpability to browser vendors for the state of affairs. I encourage you to revisit that, plenty of blame to go around.
Sure. But that's an occasional need, while not enforcing a minimum font size means hitting C-+ a couple of times for pretty much every page I ever load. In any case, the icon-font problem has less to do with the minimum font size than with the enforced typeface selections, which necessarily and completely break icon fonts.
I'm not sure which portion, of the blame in question here, you contend belongs properly with browser vendors. There are lots of things they might do differently, but I don't see how this is one of those.
Then you run into someone like me whose eyes are not as young as they once were, and who doesn't care to be abused with whatever happens to be the stylish designer's font palette du jour, and who therefore uses his browser settings to apply a minimum font size and a set of preferred typefaces which page styles aren't allowed to override, and then everything goes to hell.
Can you argue that it's my fault, not yours, that your page doesn't render well under the requirements I impose on the web content I consume? Sure, you can so argue. But every time you have to make that argument with a user, even if you win the argument in that instance, you're still both limiting your potential user base and risking a perception that you're less concerned with your users' needs than with satisfying your own desires.