From earliest times, Mankind has depended upon the availability of 'Wood' to heat and light their homes and cook their foods.
The storage of the 'Wood' has, in the process of time, become something of an art form in that if it is not correctly stacked, the exposure to the elements will cause the 'Wood' to deteriorate and more importantly, attract infestation and thus cause discomfort rather than relieve it.
Therefore, it is generally accepted that the top of the 'Woodpile' should be covered, whilst the sides allow for the air to flow throughout it and in so doing hasten the drying process of green 'Wood'.
Naturally, as is common with almost every procedure undertaken by Mankind, certain 'Adages' (or sayings) spring up which are applicable to whichever act or function such procedures may be attended by them and 'Woodpiles' are no exception.
Since the preservation of the 'Wood' is of paramount importance if it is to serve it's purpose, strict observance MUST be given to the structure of the 'Woodpile' and it's position (away from the house) and protection from damage becomes critical, particularly in inclement weather conditions.
Thus the old 'Adage' of "Dew in the Woodpile" was born, since the constant exposure to 'Dew' would of course be detrimental to the 'Wood'.
Somewhere along the line, a 'Wag' (possibly through misinterpretation or mishearing) must have misconstrued the meaning and, sensing that the 'Adage' was applicable to ANY situation that might describe a 'Spoiling' of something good, immediately associated the message which the 'Adage' delivered, with a 'Jew'.
Hence, we have an accepted version of "A Jew in the Woodpile" which is NOWADAYS completely at odds to it's original meaning and causes a great deal of anxiety to the 'Jews' BUT, as is quite in keeping with ANY criticism of whatever the 'Jews' may say or do, they have managed to shift the onus of meaning towards the 'Black' races and the 'Adage' has now become more commonly "A Nigger in the Woodpile" which is quite unfair (imho) since the 'Black' races are far less destructive than their 'Jewish' counterparts.
Another interesting misunderstanding of an old 'Adage' is "There is not enough room to swing a cat" and it is surprising just how many people associate it with 'Cruelty to animals' , surely they do not conjure images of a poor 'Moggy' being swung round by it's tail?, I believe they DO.
Cannot find any connection with 'Jews' in this one, maybe members might be able to suggest others.