Adding 250,000 lines of code to render fonts to an 1100 line functional gui library is bloat no matter how you slice it. If someone want that renderer, it's not that hard to wire it in.
And if you in particular want it, fork them and merge them.
Meh. A small C library is easier to extend than a sprawling C++ library, and it's perfectly valid to want a minimal gui that can actually import fonts. Even just building a font atlas on top of that would be useful in a lot of projects.
And if you in particular want it, fork them and merge them.