Margaret, that argument does not hold much water.
1. Soldiers. First, under most circumstances people choose to join the army, even in countries that have conscription, let alone in the US that depends entirely on a mercenary force. Even in conscription countries, you can become a conscientious objector -- which may not be convenient for you but is not life threatening either. It is quite obvious that most soldiers choose the "military glory" - some for pecuniary reasosn (career, college tuition), others for macho status, still other for the need of discipline or other quasi sexual motivation.
BTW, soldiers are not "working class" - since class is not an ascribed status or cultural identity, but the status that results form the relations to the means of production. Soldiers and policemen, while they do not own the means of production and sell their labor for wages, they are nonetheless agents of the state whose main responsibility is to uphold the existing property relations. While the selling-their-labor part may qualify them as a 'working class in itself' - the second part essentially precludes (or at least makes it extremely unlikely) them from gaining class consciousness, hence becoming a class in itself.
That leads to a more general point that working class status is not automatically a noble thing - parts of what technically qualifies as working class can be reactionary (c.f policemen and soldiers - or even so called 'labor aristocracy' in the developed countries that benefit form exploitation of labor in the developed world.
2. Milgram. As to Milgram's experiments - I think they were more publicity stunts than real experiments - if memory serves they were all based on a very similar design in which the Ss 'were lead to believe" by authority figures that they were harming another human being, and they went along with that anyway. What those expriements failed to demonstrate is what the Ss actually thought, how they cognitively construed the entire experimental situation.
In other words, I suspect that Milgram and Co. were basically a bunch of arrogant intellectuals who assumed that they successfully duped common folks into thinking what they wanted them to think. They assumed but did not demonstrate that the Ss really thought they were harming another human being, but went along with that because an intellectual authority told them so. That sounds too much like a wet dream of the scribbling class who certainly have more power than they think, but not nearly as much as they would want to have.
I can come up with an alternative explanation by assuming that the Ss construed the entire situation differently than the experimenters. Perhaps they thought of the experiment as a some sort of bizarre setup, but they did NOT think they were harming real people - because their common sense told them it was not possible under the circumstances (c'mon, what idiot would believe that they are really killing people in university labs?). We simply do not know how those Ss would have reacted had they been given orders to actually kill a person (rather than going through a set of rather abstract motions that may or may not be interpreted as so doing).
I think a more general point is that the scribbling class put too much faith in their own capability to "read the minds" of the common folks, through the use of special tools, like polls, focus groups, and experimental designs. They basically treat people like guinea pigs, incapable to subvert the 'experimental situation" out of their own will. It does not occur to them that common folks have agency of their own, and that agency includes the capability of defining the 'knowledge getting' situation (an experiment, a poll, a focus group) in their own terms that has little to do with the way the research workers define it. For example, people may be throwing back at the researcher what they think is a "politically correct" response because they have no stakes in discussing what they really think of the issue - perhaps because the issue has been framed by the researcher in such a way that Rs or Ss do not find it relevant at all, but they do not feel like taking the effort of deconstructing it, they find easier to simply get over the whole situation as quickly as possible and in the easiest possible way, and then go back to their own business.
3. Finally, the argument "kicking people on the bottom" assumes a bird's eye perspective which intellectuals who are on the top of the food chain usually take. It basically portrays common people as having little or no agency, as passive victims incapable of defining a sitiuation in their own terms (I talked about in item #2). In fact, those, seeming on the botom of the food chain can be as scheming to exploit as those on the top - think for example of pimps and sex workers.
Again, there is nothing nobele about being in a low social class. Poverty and deprivation stink, they turn people into beasts without necessarily depriving them of agency. That is a very good reason for a revolution that would elevate people from their low class status to the status currently enjoyed by a few. I think that many left-file intellectuals have a romantic view of the working class, a sort of a noble savage myth, that has little to do with reality. I do not see such bleeding heart attitudes as particualrly revolutionary or even critical - they are yet another example of cheap moralising.
Wojtek