The majority can't decide that gravity should cease to exist or the sun shouldn't shine within their borders. Some limitations on democracy are natural, others are imposed by those who established it. That doesn't mean it's not a democracy.

You could do the same thought experiment with dictatorships or any form of government really. If a dictator can decide that he'd rather have a democracy, then he can end his own existence (fine?), unless he operates in some constitutional framework that enshrines him as the one and only power within the country. If that's the case, is he still a dictator? Short answer: clearly. Long answer: We can have a long debate about this and essentially come to the conclusion that either whatever definition of democracy/dictatorships you're using needs to be revised, or you need to come up with new names for most political systems on earth, because we need to names for things at the end of the day.

In any case don't use the article author's definition:

> Democracy is a system of majority rule in which each citizen has one vote either in deciding the policies of the government or in electing the rulers, who will in turn decide policy.

According to his definition the majority is allowed to just decide policy. I don't think he realizes there's actually no contradiction if you define it like that, because ending democracy would be a matter of polity and probably politics in general, but not really a matter of just policy.

Edit: Fair warning, I edited quite a bit above roughly 10 minutes after posting.