The argument that Harriet Tubman wouldn't want to be on the $20 and that it disrespects her and appropriates her to use her that way.

I had not thought of this argument until I read Steven Hayward at Power Line making fun of it:

After years of complaining that America’s paper money featured only dead white guys, a lot of folks on the Left are in a snit that Harriet Tubman is going to replace Andrew Jackson on the face of the twenty-dollar bill.... If these people were any whinier they would be kicked out of pre-school....

Hayward links to Feminista Jones (a mental health social worker). I'll excerpt a different quote:

[I]t’s clear that putting [Tubman's] face on America’s currency would undermine her legacy. By escaping slavery and helping many others do the same, Tubman became historic for essentially stealing “property.” Her legacy is rooted in resisting the foundation of American capitalism. Tubman didn’t respect America’s economic system, so making her a symbol of it would be insulting....

Harriet Tubman did not fight for capitalism, free trade, or competitive markets. She repeatedly put herself in the line of fire to free people who were treated as currency themselves. She risked her life to ensure that enslaved black people would know they were worth more than the blood money that exchanged hands to buy and sell them. I do not believe Tubman, who died impoverished in 1913, would accept the “honor,” were it actually bestowed upon her, of having her face on America’s money.

It's such a huge honor to get your face put on money that we may lose sight of the fact that the government is taking a private individual's identity and using it for the government's interest in branding its currency. With a U.S. President, we can infer that the honor would be appreciated and the use of his face granted freely. But with someone who didn't voluntarily assume a position within government, it's harder to make that inference. Why does the government high-handedly assume the woman would give herself to the government's enterprise of merging its cash with lofty values and moral weight?

Power Line's Hayward also links to Steven W. Thrasher at The Guardian, who makes a somewhat different argument:

[T]here’s something frank and honest about [Andrew Jackson] occupying the 20 dollar bill. I mean, who better to represent what the US treasury has bought, and for whom it has amassed its tremendous wealth, than Andrew “trail of tears” Jackson?...

As historian Greg Grandin recently wrote: “Banks capitalized the slave trade and insurance companies underwrote it.”... This is the shit Tubman was escaping: the enslaved exploitation of black bodies for white profit. And it still happens today....

I am getting tired of the whitewashing of racial exploitation with brown faces. Enough with bullshit like McDonald’s slapping MLK’s face on their predatory and poverty creating labor practices.... Putting Tubman’s face on the $20 would only obfuscate how much exploitation there is still left to fight in America....

Thrasher's idea there is not so much Tubman's self-ownership and the importance of figuring out whether she, personally, would agree to play a role in the U.S. government's currency-branding project. Thrasher isn't talking about how Tubman herself would feel, but how he — and the people like him — feel. He's here now, concretely — on the pavement, thinking about the government — and he doesn't like it. He himself appropriates Tubman: her image and identity should be preserved for use on the things he supports. She belongs to him and the people he thinks he speaks for, and he wants to decide where she goes.