It doesn't matter what election system we have, so long as people are willing to spread and believe questionable claims of vote rigging. For example, there was a claim doing the rounds that Trump won because the GOP systematically purged black voter registrations in the three key swing states in numbers larger than his victory margin - if paper voting was used, that would just be the more prominent claim instead, or conspiracy theories about the paper votes would. (The mechanics of the supposed purge don't work out, none of the organisations monitoring voter suppression saw it, and no-one's been able to find the hundreds of thousands of suppressed voters that would be required - but that doesn't matter. People don't care, and rebuttals don't get the social media spread that shocking allegations do.)