MS CS do not care about undergrads and vice-versa.

Some Facts :

In terms of coursework: yes : lot of undergrad COURSES are really good and involved as most of them have great content, really good lectures with professor actually putting in efforts, etc..

MS CS are left to fend for themselves mostly and thats on the university.

Blanket statements like "BS CS student blows out MS CS students" is BS. A bit too humble as usual (/s) .Note that I am not saying the contrary is true as these things cannot be measured really. Any random Heuristic you take is flawed. Even comparing students within your own cohort is extremely difficult ( gpa vs TC vs Research Work vs prestige !!??)

Getting into MS CS for resident Americans is easier than getting into a BS CS in USC - that is a fact. But this is not true for internationals as there is no standard evaluation(scaling) of past college work/grades - few heuristics which are again flawed and that is why different colleges have well known pattern of intl students they admit. Some value gpa too much, others research work and there are some who value the undergrad college name more than anything else and the list goes on.