Ok, I would not go so far as to say that the villains of today are history teachers, but as a history teacher you might reflect your attitude towards royalty (as it used to be).
Source: The seventh comment on the article here: http://www.thehistoryblog.com/archives/28426
Do you think that "as" is necessary in the part "so far as to"? And what kind of the structure is the passage in bold? Is it some sort of the condensation of the subordinate clause in the form of the infinitive?
As far as X is a comparative construction serving as an ordinary locative designating the "goal" of the motion verb go; it provides a measure of distance:
How far will you drive today? We hope to go as far as Durham today, and then on to Edinburgh tomorrow.
In your example, go as far as is used figuratively to signify that what one does (in this case what one says) may have a greater or lesser "extension", analogous to the scale of distance, on some other sort of scale: a scale of caution or daring or violence or exaggeration, or whatever scale is in play. With that use, the figurative locations on the scale (Durham, Edinburgh in my example) may be expressed as more or less [cautious/daring/violent &c] actions:
I will not go as far as to install cameras on every corner.
She went as far as to tell him to his face that he was incompetent.
In your example, the writer rhetorically "stops short" of the extreme position of saying that history teachers are the true villains of modern society—suggesting, as stangdon and John Feltz say, that all that restrains her from "going that far" is her sense of decorum.
The phrase "go so far as to (verb)" is an idiom. It's always used this way.
"I would not go so far as to say that X is Y, but I will do Z" or "but you should consider W" is a way of coming right up to a line, but not crossing it. Often it's strongly implied that the only thing holding you back from just saying "X is Y" is that it wouldn't be polite or it would be misunderstood.
To paraphrase your example
I wouldn't normally say that the villains of today are history teachers, but if you don't reconsider your attitude towards past royalty, then you would be.
Yes, the as is necessary. to go so far as to say is kind of an idiomatic stock phrase that means something like "to say in these exact words" or "to dare to say" and has the implication that the speaker is thinking something similar but maybe not as severe.
In general, "I would not go so far as to say X" = "I would not exactly, literally say X." For example, someone might say, "I wouldn't go so far as to call Senator Pibbleton a thief, but I do think he took some liberties with official funds."
The use of as here is fairly standard - think of it as being the same as any other as in a construction like "The river is not as far away as the mountain."
