Yes, that was the case. I was being sarcastic. Zuck wrote facebook in PHP and spent millions of dollars then writing a custom interpreter to let his janky code run slightly faster than normal.
Zuck's obvious mistake: he should have written the PHP compiler to precompile chunks of GPU code that would be the only code that actually runs when serving web pages. </sarcasm>
Facebook isn't really a comparable problems, because ALL of the performance-critical code in PyTorch does runs on a GPU.