I'm not at all sure what you meant by the term witchhunt but you should be advised that in the States it has been used in a very inflamitory manner in both the 20th and 21th centurys.
The term witchhunt is normally a very biased term used to semantically skew an argument in the user's favor. The most famous witchhunt in the history of the US took place in Salem, Mass. According to ALL accounts, no witches were ever found in Salem.
Moving into the 20th century, Arthur Miller wrote "The Crucible", which takes place in Salem during the famous witchhunt. Of course, the real deal about "The Crucible" was the fact that it was actually a commentary on Senator Joseph McCarthy's activities and those of the House Un-American Activities Committee.
The idea of linking McCarthy, rhetorically, to a witchhunt was brilliant, however disingenuous. Once his cause was linked to a heavily front loaded word like witchhunt he never had a prayer. It didn't matter that history has shown that the vast majority of those he accused of being Communists were later proved, in fact, to be Communists. He was forever hopelessly linked to the term witchhunt, with all of it's rhetorical connotations.
When we choose to use the word witchhunt in a question we must remember the rhetorical power it has and how the language that both sides tacitly agree to use may very well determine the outcome -- regardless of what the actual facts were. As an example, the witchhunt in Salem failed to turn up even one witch. What has been discribed as "Joseph McCarthy's Witchunt" found many, many, many Communists. SEARCH for "venona intercepts" if you think that there were no Communists in McCarthy's Witchunt.
My point here is not about McCarthy. My point is that this 'discussion' has been couched in terms that have been used in a very inflamitory way, in many arguments in the States in the last ~60 years. IMO it is a very bad choice of words for a civil, above ground discussion.
Now, back to the question: Is there a witchunt going on? Well, since the vast majority of us (myself included) do not think that witches exist at all, and since I know that the US does, in fact, have a huge illegal immigration problem with tens of millons of illegals running all over the place -- I would say no -- it's not a Witchunt.
While I am 100% in favor of the lawful immigration into the US there is no upside to most comments made to a thread with a title that is as emotionally and politically and rhetorically charged as this one is. A differently worded Subject would have served the OP better, IMO.
IMO.