I have written about how a key element of the problem is a culture of political discourse that focuses on attacking the motivation of an advocate of ideas, rather than the ideas themselves. The constant implication that an "impure" motivation should lead to the ideas being disregarded a priori, without any need to examine their instrinsic merits.
The words we have all become wearily familiar with - racist, islamophobe, antisemite, bigot, prejudiced, etc. - all convey this charge that a person's motivation is impure and what he or she says should therefore be disregarded by default. Almost everyone reacts to the charge of impure motivation by protesting that their motivation is pure ("I'm not a racist", "not an islamophobe", "not an antisemite"). Thus, on the rare occasions that immigration, race or Islam issues are critically discussed, 98% of the discussion centres on the moral purity of the critic's motivation. It takes enormous strength of character, principle or understanding to respond instead by saying that a person's motivation does not matter; that ideas matter, and that their intrisic merits can be examined without the need to speculate about the psychological state of the person who formulated them.
It has always been something of a mystery to me where this inquisitorial culture came from and how it achieved its iron grip. Yesterday, I believe that mystery was resolved. The epiphany I had, and the understanding that came to me, I think is one of the most important insights I have achieved since I began this effort at understanding.
I quote from the book "The Criminal Code of the Jews" by Philip Berger Benny, written in 1880.
CHAPTER V. THE RULES OF EVIDENCE.
The rules of evidence, as formulated in the Talmud, are of a remarkable character. They are in most respects unlike those of any ancient legal code ; and are diametri- cally opposed to our modern English prac- tice in every important particular. The primary object of the Hebrew judicial sys- tem was to render the conviction of an innocent person impossible. All the ingenuity of the Jewish legists was directed to the attain- ment of this end. Everywhere the punish- ment of the guilty seems subordinated to this principal consideration. The credibility of witnesses must be established beyond doubt ; their impartiality must be placed above sus- picion ; the likelihood of prejudice animating any person testifying against a prisoner must be carefully sought out. The admissibility of evidence was determined by a series of stringent regulations disqualifying in each case a number of individuals from coming forward as witnesses. No man could incriminate himself ; nor could a wife give evidence against a husband. (Among the Hebrews a be- trothed girl was regarded by the law as a married woman.) On the other hand, a prisoner was not debarred from testifying in his own favour ; any argument he wished to urge, irrespective of its legal worth, was heard by the judges. Relatives — including many allied by marriage, and nearly all those allied by blood — were incompetent to appear as witnesses. Grandchildren formed, however, an exception to this rule. Those standing in loco parentis to the accused at the time the alleged offence was committed or when the trial commenced ; the shushbin — best man, groomsman — during the seven days of marriage ; an enemy, i.e. one who had not spoken to the prisoner for a period of three days, owing to dislike or hatred or on account of differences ; a creditor ; any person to whom the accused had lent money ; all who publicly and derisively — Ufrase — acted in contravention of the Mosaic laws regarding food, cleanliness, and decency ; all such as had been convicted of attempting to wrong or defraud a neigh- bour (the Talmud regards such persons as worse than those who sin against Heaven only) — these, and all others who were dis- qualified from acting as judges in a cause, were declared incompetent to appear as wit- nesses. The rabbins carefully made allowance for human weakness and natural promptings. They did not expose relatives to the tempta- tion of violating the sanctity of their oath ; and they spared father, or son, or brother the pain of being compelled to speak the damning word which should consign, perhaps to death, one near and dear to them. Thus, the partiality of friends, the affection of relatives, or the enmity of opponents, could in no wise affect the issues of a trial.Source
It is clear, then, that the question of motivation was critical in the Jewish legal system. A witness who, on any grounds, could be accused of wishing the defendant ill; who had a history of antagonism towards him, or connections to someone who did, could be disqualified as a potential witness. Since there was, in general, no means of securing a criminal conviction absent the testimony of two qualified eye-witnesses, defensive legal strategies must have focused on impugning the motivation of potentially adverse witnesses. This has clear and obvious parallels with the accusatory style of discourse that has come to dominate discussion of immigration and related topics. It also explains the associative element in Jewish discourse. It is very common to see Jews impugn their opponents by establishing that they have some connection to some person or organisation that is already presumed to be "tainted". We can see that this comes straight from the Jewish legal system in that witnesses could be impugned if they were, for example, related or otherwise connected to someone else whose motivation might have been considered impure.
This type of accusatory discourse is pernicious because it makes rational debate impossible. The quality of a person's motivation can never truly be measured or known. So debates about it are irresolvable. Nor does it even matter. It is what a person says that matters, not why they say it. Anyone can impugn anyone else's motivation for saying anything. Like weeds, when this style of discourse profilerates, it clogs up everything else. Ultimately, it is threatening to the continuation of democracy and civil peace. Now we know, or must strongly suspect, that its source lies in the traditions of the Jewish legal system.