I will always argue against pure democracies. People are not invested enough to provide a coherent opinion on 100% of the solutions our societies require for survive and thrive.
A vote over the use of chemicals for water treatment could easily end in their permanent ban. Hell, with the right malicious intent, someone could easily get dihydrogen monoxide banned from crop fields.
A pure democracy is how Idiocracy becomes a reality. Now, a mix, such as a republic electing the careful use of democratic socialism… Sure!