This is perhaps not the most eloquent response: well, duh. All of the above mentioned groups receive lesser sentences probably because their extenuating circumstances are more likely to be considered (or invented) during sentencing. I am unsure if these disparities truly result from judges deviating from the guidelines since in many states judges are given judicial discretion and the sentencing ranges tend to vary drastically. The ultimate result is clear though: all these groups benefit from the presumption that they are inherently less culpable for their actions. Since our society and many ideologies support those notions, some more than others, the question is how can be addressed?