I'd argue it's more than "that it's free", it's that it's tuned to push our buttons. Specifically, it's designed to engage (e.g. generate enragement, outragemen

I'd argue it's more than "that it's free", it's that it's tuned to push our buttons. Specifically, it's designed to engage (e.g. generate enragement, outragement, or some similarly powerful emotional response). And the only barrier to getting a hit of this emotional stimulant is a mere click.