Amazing, memes predicted this before national news....

That's because memes are composed by people who look at a variety of sources and then -- if they are conservatives -- think for themselves whereas the news is generally INVENTED by media outlets whom now pretty much openly working for the political interests of the DNC.

I think everyone with 2+ brain cells figured it out, and they decided to say it out loud. Kinda like how everyone knew that one woman killed her husband with fish cleaner months ago.

is she that dumb that she let it slip, or was it done on purpose as a campaign strategy?

Mainly because more people wanted Biden than they did Harris.

Well in my opinion it might depend whether you believe there is an organisation controlling events behind the scenes or not.
And if you do then you might be aware that one of their rules is you can do anything as long as you make it known in public. So whether delivered as a Freudian slip kind of spoken event or written in a document, book etc it gets released outlining what they plan to do.
Either method they then release the idea onto us and it's up to us to hear it.
Most of their announcements are more hidden by way of written publications but on occasion such as this I would say she is puting it out there because it is the plan as the world already suspected.
George w Bush told the world before the coalition of the willing went into Iraq that it was up to us to bring "Chaos out of Order" Uh I mean Order out of Chaos. So what happened after they went into Iraq, Order? or Chaos? Iraq's know even if Americans don't what the real answer was.

Welcome to the "Harris Administration with Joe Biden As President."