Interpreting "One Law" Passages: Rashi vs. Derek Leman

Derek is hilarious.  He cries out "Why do people cite these [One Law] verses repeatedly without any seeming awareness of the context?"

And then Derek expounds that the One Law passages do not apply to every command but only that of the immediate context in each occurrence (e.g. "offering of sacrifices" and "this matter [of Pesach]").  LINK

Well, Rashi, the foremost interpreter of Jewish Law (you're gonna love this) has this to say:

"49.  one law.  Not only with respect to the eating of the paschal lamb is the stranger equal to the native Israelite, but also in the duty to observe all other commandments [Rashi]."  pg. 399 of Soncino Chumash (edited by A. Cohen).