Sorry, it was poorly worded on my part. I didn't actually doubt that, but prefer not to state other people's assertions as fact unless I know it is so for myself. I prefer to have my assertions grounded by what I'm basing them on, which is less about doubt of the source and more about keeping myself honest when arguing and not taking too hard a stance on stuff I haven't verified myself, since it's easy to come across as authoritative when I don't intend to otherwise.
Thanks for the evidence though, it's always best to have, even if it can be a pain to drum up when it might not really be called into question anyways. :)
https://lwn.net/Articles/676831/