Because tatted up, ex-con, retarded white trash edgelords who are really only trying to get negative attention from normies by wearing swastikas and screaming about jews do far more harm than good for the Cause.
Not to mention the skinhead and WP music scene used to drive tons toward the cause.
Yes, tons of retarded edgelords and other losers and failures and fuckups that no sane person would actually want to associate with.
If you really want to make a difference, you want the clean-cut, successful, intelligent, well-spoken, well-informed family man who is popular and has has a good status and reputation in the local community to say the 14 words, not when some trashy wigger looking for a streetfight