Uh, you really, REALLY want to be careful WHO you listen to.
The "reviewer" is totally clueless...
Lightroom uses the Pro Photo chromaticies (the color coordinates) but not the gamma. LR's gamma internally is gamma 1. The histogram display is a tuned sRGB tone curve. But Lightroom's internal color space is _NOT_ "Pro Photo RGB".
And, when exporting, the exported file is in whatever color space you export to. Course, you only have 3 choices...the REAL Photo Photo RGB, Adobe RGB or sRGB. And, those three color spaces are the standard, run of the mill color spaces...
Please, PLEASE be careful who you listen to...and do the world a favor and don't propagate really wrong info. Jeeesh...