bcantrill is https://en.wikipedia.org/wiki/Bryan_Cantrill

If he is saying that Intel is giving other advice privately then you are welcome not to believe him (and note that it is you who is using the much stronger term "lying" here).

Personally I think un-sourced statements from him are worth listening to.

My general attitude is to presume good faith - both on intels part, and on the part of commenters online. I had no idea who he was till you raised the point with me - had he I identified some source for his assertions (even first had observation on a large number of systems), I probably wouldn't have said anything.

Not that it's a source you can point to, but I have also heard the much stronger language — don't push this microcode — trickle out of Intel.