That's what I disagree with, the two part of the post. First, either the Indian trade does not flow and you don't control Zanzibar, and then the Cape brings like 3 ducats, and it is usless, or the Indian trade flows and Zanzibar will always be more interesting to collect in than the Cape (easier to monopolize, you don't need to colonize anything and there is no "transfer from traders downstream" so long as you colonize one province, The Cape). And then, imho, to slow down the other colonizers, colonize just The Cape and let the other provinces there empty, Spain will usually colonize them one by one and lose decades.
As I stated in the post you are quoting, colonizing the Cape is best used as a stepping stone to get range in to Zanzibar. Before you get the trade power you need there, it may very well be more profitable to collect in the cape than putting a merchant in the Ivory Coast as you suggest (we are still talking about the early game). Sure, a bunch of light ships in the Ivory Coast node may be better, but they would probably be better employed in Europe in the first place.
Your post before the one you are nagging about:
Just saying that you don't need the Cape if you have Ivory Coast. Cape flows in Ivory Coast only, noone collects in Cape, so feel free to ignore Cape, that's a waste of time and a common mistake. Let Castile/Portugal lose time colonize it, they will steer towards Ivory Coast, focus on controlling Ivory Coast instead.
You basically said. "Don't colonize the Cape, your colonizers are better used elsewhere. Leave it for Castile/Portugal". Please, let us know where you want to send those colonizers in stead. Your post indicates that you would rather colonize all those 3-5 development provinces without any trade power modifiers in the Ivory Coast.