The theory behind it has always been that taxes serve as a transfer of wealth. You tax the wealthy more and reduce taxes on the less wealthy, and/or spend that money on programs and projects that benefit the poor disproportionately.

Don’t confuse how politicians sell something with the mechanism. The rhetoric changed with the rise of celebrity through wealth. ‘Soak the rich’ is a sales slogan since it’s easy to punch up, and no one has any sympathy for a guy like Bezos. The same sort of rhetoric is going on right now with lines like ‘billionaires made $2t during the pandemic’, or the headline for this article. the implication is that they actively made moves that increased the amount of dollars in their bank account by literally taking money from the poor. The reality is that they continued running their businesses according to the rules of the game and the value of their business holdings is up.

In that context ‘soak the rich’ should really just be seen as a proposed rule change to the game.