"The bug" in question refers to the one found by the bug-finding tool the article claims triggered the latest episode of debate. Nobody is claiming it's the only bug, just that this triggering bug highlighted was a clear example of where there is actually such a clear cut line.

Google does contribute some patches for codecs they actually consume e.g. https://github.com/FFmpeg/FFmpeg/commit/b1febda061955c6f4bfb..., the bug in question was just an example of one the bug finding tool found that they didn't consume - which leads to this conversation.