Right. This is how Chromium works. Chromium does not build with H.264 compatibility out of the box. Projects using Chromium (not the Chrome package Google defaults for end-users) must explicitly enable H.264.
All they have to do is add symlinks to their non-broken ffmpeg libraries in /usr/lib/chromium
You don't have to compile chromium any differently, just tell it not to use its bundled ffmpeg (even chrome only includes a few codecs), and it'll figure out what's supported at runtime.
The hobby projects which use H.264 have not been prosecuted, as far as I know, though I feel it's wrong for this possibility to exist.