Because, despite their treasonous behavior against Britain, they are nevertheless the fathers of the nation. As such, their terroristic actions are forced to be viewed in a different light. On the contrary, Harriet Tubman in her involvement with the failed insurrection against the nation, is a symbol of terrorism perpetrated on the part of individuals against the social order, not to mention an act which, if successful, could very easily have had absolutely devastating consequences for the future of the nation.

Essentially, one group - despite their treason to Britain, created America - while the other - Tubman - was treasonous against America, and as such ought not to be venerated by America after 160 years has allowed the weight of her traitorous actions to be forgotten. The ends never justify the means; no matter that her effort was to secure freedom for her people; she was not in a position to make that decision. The Supreme Court in Dred Scott v. Sandford had ruled that Negroes cannot ever be citizens of the United States, while Congress was debating on the issue and, ultimately, decided to amend the constitution to allow for the incorporation of the Negro under the concept of "man".

Citizens cannot be tolerated in taking the law into their own hands; those that do so today are shot dead by the ATF somewhere in the middle of nowhere.

the key difference being that the USA was not a nation on it's own pre-revolution. by this I mean it would be like the British putting John Hancock or Washington on their money. my point does not stand as a result of any moral issue. my point is on the issue that if we put her visage on a bill, it will be effectively rewarding those who declare themselves enemies of the state for the notion of a greater good, attenuating unrest, and creating many defectors who may have a perverted idea of what is good and breaking the law for that reason. Case and point BLM. who already are breaking the law in a perverted notion that reform must come for the USA. If we want to Stifle unrest, and make way for peaceful discussions, we should not reward those who break the law for a greater good. REGUARDLESS of what that greater good is.