I don't know how this could be true--once the country entered into the 1920s, especially in urban areas. Large port cities like New York City and Baltimore had a steady stream of new customers, so tattooists were able to ply their trades (tattooing at barber shops and tattoo parlors, or working as attractions in dime museums) in the inner cities when circus work and warm weather came to an end. These same tattooed attractions would then be subject to vast quantities of downtime in cities with numerous daily tabloids and newspapers, and too many movie houses and theaters to count. To assume that they were unaware of the cultural atmosphere because of their class standing seems to sell these women short.
Additionally, by the 1920s, vaudeville had permeated the circus sideshow and the carnival stage--even big-name actresses were taking turns on the boards to earn a little extra money--and the resulting links between vaudeville, professional theater, and the feminist movement have been previously established in academic scholarship. However, because tattooed ladies and vaudeville entertainers traveled on the same shows together, it is an easy to assume that female sideshow attractions could (and would) be exposed to the same politics and "new" feminist ideas as women in vaudeville troupes.
It is important to note that a few tattoo historians also claim that the urban, politically-motivated feminist New Woman was too involved with the suffrage movement to notice the potential future "meaning" assigned to the role of tattooed ladies. It seems to me that at least some of these New Women were aware of what The Tattooed Lady stood for to the working class--according to this photo above, she was a well-recognized symbol of independence and forward thinking.