Which, sure, there are a few naive folks like that; but the renewables space is filled with industrialists that did the hard technology work of actually creating an entirely new energy future. Come on, random Twitter dude... these folks know their supply chains and are smart enough to know that basically all reports everywhere for the past 10 years are predicting this massive shift from fossil fuel extraction to mineral extraction. Nobody is surprised.
As for the rest of your comment, none of the rest of the energy source has to be carbon based. And by saying that they are going to decarbonize their supply chain, Apple is creating a guaranteed customer for new business to actually deliver that supply. And for a new business, that guaranteed market is by far the most important factor for getting a new business off the ground. It means that no matter their costs, as long as they are better than the other decarbonized sources, they can win the bid. And that's where subsidies/tax credits are weaker, because they have to predict the delta between the earliest decarbonized product and the traditional alternatives. A guaranteed market gets around that.
For tough-to-decarbonize sectors such as concrete, having more purchasers of the zero-carbon early products, such as city governments or state governments, is a huge boom to entrepreneurs looking to pioneer a new space.
So Apple really is doing something significant, which will actually change the economy for the better, and probably more so than a tax credit scheme.
People are working on reducing demand for electricity through efficiency, but if we electrified everything in the US today, demand for electricity would something like 9x. So, yes, we're going to need a lot more copper.