...so when 4 legal immigrants commit a heinous crime, it’s improper to impugn America’s lax immigration program?
No, but when four legal immigrants commit a terrible crime, it’s improper to impugn the character of legal immigrants per se by making the general claim that they are a “vast tapestry of scum from the great ,fetid, pond of 3rd World humanity.” (see the first post on this thread; the one I responded to)
I think that one can voice legitimate criticisms of US immigration policy — lack of enforcement of current laws would be a good place to start — without descending to this level of bigotry and “know nothing” nonsense.