Hm the Google guide looks like yet another programmers personal expression of style. The "pretty print police" at work. There may be some defensible (i.e. related to actual good programming practice)comments in there, but much is the usual personal preference stuff about braces and capitalization.
Different folks internalize different features of C++, for good or bad. To take someone's comfort zone and institutionalize it is arrogant.
> much is the usual personal preference stuff about braces and capitalization.
There's nothing wrong with that; having that stuff in your style guide means that you get more consistent code, which is easier for everyone to read whatever their personal preferences.
(General point: Having a rule that says "Everyone must do X rather than Y" doesn't mean claiming, or thinking, that X is better than Y. There's not much to choose between driving on the left side of the road and driving on the right, but it sure is valuable to choose one or the other and stick with it.)
Braces are such a stupid thing to be worried about (thank you, BDFL!), but things like variable naming are very valuable in helping people parse code quickly. If you look at my code, you know instantly which variables are global constants, which are class instance, which are method parameters, and which are locals. Those are the valuable additions; the rest is an expression of an anal, alpha engineer or a group that said "let's just start with this thing I found online".
Actually most of the guide relate to good programming practices, and not just stylistic preferences. Also, I would argue that taking offense at style guidelines (which bring a lot of benefits, especially at a big software company like Google) is unprofessional.
Different folks internalize different features of C++, for good or bad. To take someone's comfort zone and institutionalize it is arrogant.