I read that as more "we cold emailed people looking for a potential contact" than "we submitted this vulnerability to their PSIRT". The fact that they say this is not a vulnerability disclosure situation suggests that they did not use the vulnerability disclosure communication methods.

I read it as "we tried contacting them through their standard processes, and were told it didn't fit in" but I can see your reading now that I've gone back and reread that specific section again. It's indeed quite vague as if they were the ones that made the decision or Toyota.