Sure, you can call it what you like; what matters is, does it deserve the same negative connotation as "cartel"? The answer to that depends on your position on:
> Ultimately taxes going to zero is a good thing because it is a sign of competitiveness between tax structures favoring more efficient governments.
...which is incorrect, because "efficiency" is not tax rate alone, it's tax rate compared to services offered. We're not talking about countries cutting their tax rate because they're more efficient; Ireland doesn't know how to build roads cheaper than England does. We're talking about countries that decide to cut their tax rate and cut services proportionally in order to entice immigrants. They aren't any more efficient the day after they do that than the day before, they're just selling a shoddier product at a lower price point.
And it's worth pointing out, if you think of government as a product and tax rates as the price, the reason we have this problem in the first place is that the market is broken by allowing corporations to "buy" one product but "use" another. For a company to primarily operate in the USA but pay corporate taxes to Bermuda is roughly equivalent to a man who drives off the lot in a new Benz but is making payments on a used Buick. If the market were functional - if the "price" a corporation chooses to pay in deciding where to be patriated were aligned with the "value" they receive in access to infrastructure and markets - we wouldn't be here discussing this agreement because it wouldn't be needed.
Imagine you and I are neighboring farmers who irrigate our fields from the same river. Our farms grow, as does our water use, until we're each using half the water. I buy a bigger water pump and start sucking up most of the water, leaving you with dying crops. So you go out and buy an even bigger pump; now you're getting most of the water, and some of my crops are dying.
What's the result? There are only two outcomes here: either we agree to split the water, or we spend more and more money on larger and larger pumps until neither of us has any profit left over. The latter outcome is the "trap" - neither of us wants to spend every spare dollar on pumps, but unless we come up with some agreement, that's what will happen.
Also once the US can manage to get 130 countries to agree to its tax regime in one area, guaranteed it won't stop there.
I'd say that this however is not a resource sharing situation. It's a competition for the magical money tree of corporation taxes. And that's a good thing, because "setting up an environment in which businesses cannot thrive" is often a vote winner, but is a terrible idea.
Anyway, you're right that this a competition for corp tax money, and that it could be bad in theory if there was no competition for it, since e.g. we could all collectively agree to set the corp tax rate too high, which I agree would be bad. But there's no ratchet effect. All we have to do to avoid the "taxes too high" problem is be aware of it and decide not to do that, whereas we cannot avoid the "race to the bottom" problem by being aware of it, we need an agreement like the one described in the article.
This method contains no incentives to do it (competition) and no way to establish what is "too high" (also competition).
The argument is, is that poorer countries, especially those with natural resources, would do better nurturing their own corporations, rather than creating policies to attract foreign corporations.
The end result of preferring foreign corporations is a race-to-the-bottom where the end result is that corporations become a law unto themselves, operating as if they miniature states within the host state.
The point of this measure is to avoid a coordination trap that leads to corp tax rates converging on zero even though each country does not want that. Such scenarios are well studied, and a mutually agreed upon enforcement mechanism is the optimal solution. If that resembles a conspiracy theory to someone, well, hopefully they can read the wikipedia page on the Prisoners' Dilemma and learn something new.