The US is a democracy. It is also a constitutional republic. There's no conflict between the terms.
The Heritage Foundation is smart enough to realise the EC favours Republicans and therefore the policies it promotes and so will spin anything to make that seems like a good idea, because the will of the people being enacted would work against their goals.
Finally, and more a reply to the parent comment, even a popular vote within a two-party system can be suboptimal in some ways and so be less than an ideal "democracy". Ranked choice voting or similar systems can stop "regulatory capture" of the two main parties from denying the voters a legitimate voice.