Correction: she got 400k people to click a link where they can get information about registering to vote in their state. Whether those were unregistered voters and/or if any of those actually went through with registration remains to be seen.
Because they want to fuck her- not necessarily only because they are attracted to her, but because she is a highly successful, outspoken white woman they would like to "show her place."
In other words, it's a power fantasy- consent not required.