The Goldilocks Diversity of Christianity

There is a meme going about which seems to attack Christianity's credibility on the grounds of hyperdiversity:

First of all, I think diversity within Christianity should be considered a strength. Ironically, secularists tend to be politically liberal, and diversity is considered a liberal value. So why would they level this as an attack? It's hypocritical.

Perhaps more importantly, the meme is not accurate. Of course the meme is shared without a source, and I've asked for a source and I've yet to find one.* When one simply googles 'how many denominations of christianity', the top result is this article which convincingly argues, \"...there are not 33,000 Protes­tant denom­i­na­tions. There are not any­where close to it.\"

*Update, 10/5: The original poster gave the following comment: \"According to The Center for the Study of Global Christianity the current number is 48,000 but I could not find their definition of denomination.\" I also started a related Reddit thread here.

The article goes on to show there are in fact orders of magnitude fewer than that many denominations in all of Christianity. The 33k number is at least traceable to a source, incorrect as that source may be. As explained in the article, the Roman Catholic church is split into hundreds of denominations because the scholars measuring 33k denominations use a definition of a denomination which is almost universally rejected by Christians. Most Christians recognize the Roman Catholic church as a single denomination.

Christianity has a significant amount of diversity, but not so much as to create a problem. It's arguably a very healthy or goldilocks level of diversity. Consider the following:

1. Over 2.15 billion of the world's approximately 2.3 billion Christians belong to less than 20 denominations. That's over 93%.
   1. The Roman Catholic church represents over 1.2 billion Christians
   2. The Eastern Orthodox church has more than 250 million members.
   3. There are over 450 million members of these 6 major international protestant denominations.
   4. Over 150 million members in the 7 largest national denominational bodies.
   5. Over 125 million members in the 5 largest non-national, non-international bodies.
2. Hundreds of millions of Christians belong to national denominations. These denominations generally reflect organizational separation for legal reasons, not theological differences.
3. Where denominations disagree on theology, it is usually in the realm of inessential doctrine. I think CARM does a really great job of elucidating essential vs inessential Christian doctrine.
   1. A very similar notion to the idea of essential doctrine is the term 'Mere Christianity' from Baxter and Hooker, refined by C. S. Lewis. This term refers to \"the belief that has been common to nearly all Christians at all times.\" Essential doctrine is plausibly an equal set or a subset of Mere Christian doctrine. Many Christian apologists focus on defending essential doctrine.
   2. The fact that such diversity exists without jeopardizing essential doctrine actually helps to evidence the robustness of that essential doctrine.