Agreed. The Bill of Rights is anti-democratic for the purpose of reining in the majority when it tramples the rights of the minority. Then, there are the anti-democratic measures, like representation in the Senate, whose purpose is to provide a balance and separation of powers. The electoral college's purpose was to get the slave states on board.
All those purposes are in service of trying to create a functioning democracy.
Towards the end of WW2, and later when the proto-EU was being set up, ideas of forming superstates, federalism and so forth were in the ether. The Kantian idea of peace through uniting Europe. Once you start thinking about continental government in this way, the idea of world government naturally pops up.
The typical argument I've seen against the feasibility of this from the 40s/50s has been that the people of Asia, Europe, South America etc.... are too culturally different to be under a common government that they would identify with. At least that would be an obstacle for any foreseeable future worth worrying about.
Jean Monnet, one of the key people behind the creation of the EU had an idea that if you just imposed the institutions of a superstate over Europe, identification with nations and national difference would whither, and a new European Man would emerge. He hoped that the EU would slowly expand into Africa and Asia in this way.
Some of his ideas seem to come from Communism - the Communist Man that would appear when True Communism had been achieved. A lot also came from the time he spent in the US where he thought he saw this process of a common identity being forged, and the States fading into the background, well underway.
It seems to me that, unless one supposes that a deracinated Federal/European Man, of the sort Monnet imagined, can somehow be induced to appear, then the programme of unifying a collection of people with very different views about life under a centralised government isn't necessarily achievable. The closer you get to it, the more resistance you will create.
The recent history of Europe and the US doesn't make me optimistic about the achievability of this idea to turn the nations of Europe or the States in the US into irrelevant anachronisms. Maybe mass immigration with be enough, I don't know. It's still a problem though that I don't think can be ignored. January 6th is just that issue bubbling to the foreground again.
That is in sharp contrast to the current anti-democratic measures from Repub state legislatures (we can include gerrymandering by both parties in here, too) whose purpose is to keep power.
Gerrymandering is one of those things that it is hard to stop unless one believes that bureaucracies can be trusted to be apolitical, and will be seen as apolitical. My preferred solution is to make sure that redistricting has to be approved by some individual or body that represents the majority of the impacted citizens. We generally think our enemies motives are dirty and ours are clean. I would rather consider these issues in terms of their effect rather than the secret reasons we think we detect.
Because we can use the same word, "anti-democratic" for both doesn't mean that both are equally within the spirit of the Constitution, even if both are legal. And I'm not minimizing its problem by calling it (merely) outside the spirit of the Constitution. That can still be fundmentally problematic.
Any system that sets up blocks to the majority of citizens instantly getting their way is necessarily anti-democratic in some way. Every sentence of the Constitution that limits the power of government is an affront to democracy since in limiting the government that represents the will of the people, the Constitution limits the people. Perfect democracy is tyranny. Arguments that take something as being anti-democratic to be synonymous with bad are bad arguments.