They don't lack the understanding, they are simply paying enough attention to understand that the administration is already breaking the law and flagrantly violating the constitution. The prediction is not that the administration has the authority to cancel or postpone elections legally, but that they will try anyway. It is a reasonable belief, given all the crimes that they have committed so far.
> If you think they're going to just outright coup and push that past the whole of the other branches of government, say so.
That is the implication, yes. Before you dismiss it out of hand, remember that the president has already attempted a coup once before.
So the situation we are in is apparent to anyone who has actually been paying attention: Congress is functionally non-existent right now, having given up congressional power over both taxation and war. The Supreme Court has demonstrated repeatedly that they are in the pocket of the administration, and even if they change their mind at the last minute when they realize they too will lose power under a dictatorship, they have no way to actually enforce their rulings.
That leaves it to the states, roughly half of which will align with the administration, against the federal government. Bear in mind the distinguished individual currently in charge of the DoD is an alcoholic and religious extremist and under his leadership commanders throughout the military have started to refer to the war with Iran as a Holy War. [0] So it is unlikely the military will side with the constitution.
[0] https://newrepublic.com/post/207270/military-leaders-iran-wa...