Extremists do not respond well to criticism. They are legends in their own minds who believe themselves to possess pure truth. Any words that violate that delusion trigger impotently angry responses without substance. These various non-arguments have become favored thought terminating cliches.
"Thats just a smear!"
The s-word (no not ) is beloved by most extremists, it amounts to "the critique is slander because I say it is." Obviously it must be proved that criticism is baseless defamation, simply claiming it to be proves nothing. The acceptance of the quoted tactic would come with a heavy price: any criticism made by extremists would be rendered null and void. If shouting smear so strenuously sends any criticism into the cornfield then your opponents can do the same thing.
Its only useful as an insight to the extremists' mentality. They believe that they are always correct because their ideology is absolute truth, the mindset that has lead to so many atrocities (fortunately the people I wrote this post with in mind only massacre quality of the internet). Therefore any criticism of them must be false.
Fringe ideologues and usually hypocrites, the habit of crying 'smear' is often made by those who genuinely defame people. When notorious Jew hater Ali Abunimah libeled Thor Halvorssen (and providing the internet with unintentional comedy only rivaled by militia members insulting the SPLC) Ali mewled that Thor had 'smeared' him. Its also central in alibi anti-Semitism, someone defending Jew hatred will claim will claim that they or someone else was 'smeared' as an anti-Semite.
The smear defense can be so false that it can defy comprehension. When Mona Seif was criticized for tweets about Israel various bloggers leaped to her defense like the toad taking a bullet for magneto. Her defenders insisted that she was a noble lady 'smeared' as anti-Semitic for criticizing Israel. Yet her own tweets described attacks on Israeli civilians as legitimate "resistance" and she was angry that anyone even raised the possibility of such attacks coming to an end. Dead Jewish civilians elate her, the thought of such violence ending enrages her.
Mona stated her support anti-Semitic slaughter was written in English to make her position clear, she may be a soulless Jew hating abomination but she is at least unlike her fans. (Its difficult to tell who's more immorally perverse and putrid, Mona or her defenders.) Sometimes resorting to crying smear often suggests that a critique is correct.
"That is a violation of academic freedom."
Academic freedom has become a battle cry against criticism and academic accountability. People who cry academic freedom have a childish belief that tenure is a gawd given right, not a privilege that can be revoked. Academic fringe ideologues and their fans view academia as a refuge from the real world. Where else could you churn out barely comprehensible semi-literate bilge in service of adolescent identity politics and get paid for it in money instead of guffaws?
The idea of academics being removed and/or censored for opinions is absurd since it would only cripple their respective universities. That concept is central to moans of 'academic freedom' and it can be refuted since extremist frauds in academia remain fully employed. Thomas Dilorenzo has written some of the most racist and comically inaccurate books ever published, he insulted Boston bombings victims by defaming them as 'bootlickers.' Joseph Massad's body of work is almost entirely homophobic, misogynist and anti-Semitic its heavily inaccurate as many critics have documented.
Both men and others remain fully employed and tenured at the colleges which are degraded by their presence. That doesn't stop them from trying to cannonize themselves as martyrs. Dilorenzo has whined about "he academic left's attempted silencing of dissent" which should offend those who "believe in academic freedom." Massad claimed that the campus watch website is an affront to "academic freedom" and an attempt to "to terrorize faculty into following the Israeli line and to intimidate us by having us avoid addressing thes issues." I don't trust CW as a source but seriously 'intimidate' and 'terrorize?' Usually someone's imagined victim status is the direct inverse of their actual status, its hard to imagine Massad being terrorized by something other than spiders or the idea that the people who hired might actually read his work, fortunately for him its barely comprehensible.
Obviously if there was a policy of eliminating perfessers for certain views Massad, Dilorenzo and an entire rogues gallery of frauds would have already gotten the boot thus improving our universities which exist to teach people. They do not exist to provide a forum for those who try to make their delusional identity issues (whether its the idea that the confederacy was a utopia or that Arab culture is beyond criticism) fact. If anything we need less academic freedom to make sure that our universities mold our young people into capable adults instead of producing manchildren addled with extremist mythology.