I don't disagree, really, with much of what you say, except with the idea that "those grousing about this being a 'step in the wrong direction' don't have much ground to stand on - yet". While I'm sympathetic to the assertion that much of what Trump himself said was mis-stated or mis-characterized or otherwise retroactively clarified, at the same time there is a non-trivial contingent of his supporters who actively cleaved to and celebrated the worst interpretations of those statements, who were emboldened to verbally (and sometimes physically) commits acts of outright bigotry, and who now likely feel even more vindicated about that posture and those sentiments—sentiments that went well beyond anti-illegal rhetoric and wishes to tighten immigration regulations.
I think many of the voters Trump decisively poached, especially in the middle west, had genuine (if, in my mind, somewhat misplaced) concerns about illegal immigration and its effect on their family's economic viability—and I am genuinely empathetic, even though (as I said) I think those concerns are misplaced, focusing on treating a symptom and not a cause. However, there is also small but very loud section of Trump voters (some self-identified "alt-right", some simply more conventional assholes coming out of the woodwork) who can and should legitimately be called "bigots"—and yes, it's important we not deploy that word "freely and indiscriminately", so it still has accuracy and authority when it is used legitimately.
