My understanding is that when the phone is idle, bars are commonly measured based only on the quality and strength of the incoming signal. The outgoing signal might be stable enough for a handshake but not for a call.
Of course the other possible explanation for full bars but no calls is that the network is busy.
Carries can save money by having less towers but by using higher transmit power. I have heard that this can show up as the phone reporting full bars, but not being able to initiate/receive calls due to insufficient transmit power in the phone.
I think the writer was talking about communication skills instead of country of origin.
At least I would think twice before applying again to a company, that hasn't previously answered my job applications in due time, so I definitely agree with the writer on that one.