That style is only called by the shortcode, and will directly pick up whatever color the font is in the rest of the text. So you're supposed to either use the color argument in the shortcode (example) or properly use css for the surrounding elements. There really wasn't a great way to allow on the fly changes otherwise.
Also that bit of code has been that way since version 1.2 so it's not new and I suspect is not the cause of your headache...
Try using the class 'genericond' in your css, as its more exact and won't conflict with other themes and plugins that include Genericons.
If that doesn't help, what's the actual code in your post, and what's the CSS that isn't working?