It doesn't make sense to do such a thing because the functioning of the propaganda is at a much different level.
Media is inherently biased.Often times, there is an intention and a desire to manipulate (often in a deceptive, counterfactual or psychologically operative fashion) the cognitive process of the reader to obtain some behavioral/operational semantics. Therefore, this service rewrites web pages to conform to terminological standards representative of some particular worldview or perspective (including so far as to include "foreign" languages). It has been suggested to call this system metabias.
War on Words substitutes various expressions in common use that have deceptive effects.The only lesson here is really this: Perhaps you need not know what is in the library if you can understand why some people would want to burn it down!
In otherwords this is a very direct counter-propaganda system.There are more sophisticated ones but we have not bothered to create them because they would likely be misused. This is somewhat likely to be misused, especially when they completely control the media with DRM and so forth.
There are various attacks that can be used against such a content post filter, and should be guarded against.
Oftentimes they will not include enough information in order to disambiguate the actual meaning which makes it difficult to understand.