You're not very perceptive, are you.
Here's how he framed his comment:
"You think these people are subhuman.... The Jews were looked upon the same way people are viewing Mexicans now."
What he's saying is that the concerns expressed here on FR about the rule of law, the use of taxpayer benefits, the denigration of American values, and the principles of equal protection are really not important, or perhaps even red herrings.
Red herrings for what? For racism. Because the Nazi movement - which he invokes when he says "Jews were looked upon the same way" - was at rock bottom a racist movement. The Nazis despised what they called "the Jewish race" and sought a "pure Aryan race". Goebbel's vile and insidious propaganda film "The Eternal Jew" is kept under lock and key (and has never had a public viewing") precisely because its strives to to define a "Jewish race" with specific physiological and cultural features as a "subhuman", rat-like entity.
So what he is saying is that FR posters are actually Nazi-like racists, whose concerns about immigration and the national welfare are false.
When someone is fixated on diverting a political discussion from one of fairness and legality and actual pragmatic public policy concerns, to the tawdry and uni-dimensional slur of racism, then I know where that person is coming from.
They elevate race above all other considerations, and presume (no, insist) that everyone else does the same thing, even if they are not aware of it.
Such people are by definition, racists.
To call somebody a racist does not make you a racist (and this argument is surprising since I would expect you would realize the irony of reflection upon yourself). And even if it did or if diverting attention somehow did, it is not a valid reason alone to label somebody a racist. It does not meet the criteria I recommended to be sure beyond any reasonable doubt (because you have not clarified if the action or statement was intentional—consider the fundamental attribution error).