Well, rationality doesn't exist in a vacuum. Those societal pressures are taken into account in a rational choice.
> Are psychopaths not a good indicator of what might happen if your self limiting emotions/thoughts were turned off?
Possibly? If your goal is the ultimate advancement of the self, then sociopathic tendencies might yield the best results. We've evolved to have strong emotions regarding our offspring and those of our tribe, because that's proven a beneficial strategy for the species, but that is, in some respect, to the detriment of the individual. Most of us are fine with this decision, because of our feelings regarding our and our future offspring, but if you have no care for family, friends or the species as a whole, then gaming the system for your own advancement is probably the rational choice.
There are interesting implications to your sentence though. The blogger explained the loss of (generally perceived as) negative emotions, but what if they were not put in a situation to notice, or were unable to because of the condition itself, a loss in what we generally perceive as positive emotions, such as empathy and sympathy? This of course assumes that there was some emotional state change, and it wasn't a placebo effect.