Height has nothing to do with intelligence, which is what the discussion thread is about.
+5 SD change in intelligence (ie, average IQ of 175) would be amazing, but it's not obviously impossible. So it's "on the table" in the sense that cities on Mars are "on the table". It's not prohibited by any known laws of nature, and some experts are working on it.
There are lots of actual lies in circulation, so I encourage you to reserve the use of the word for things that are demonstrably false, not just ambitious claims that one might be skeptical of.
Stretching the truth like this is lying, whether you like it or not.