Trading is not a zero sum game. It doesn't matter if nothing's being made, that's not the point. It's an important service providing pricing and liquidity which facilitates capital allocation, diversification, and risk management. Trading is an absolutely essential part of the economy.
As a simple example, a farmer hedges his wheat crop selling wheat futures. That allows him to reduce some of his risk, thereby allowing him to plant more (i.e. growing the economy). The market marker who bought the wheat futures may be trading multiple commodities. This trade diversifies his risk, allowing him to trade more of other commodities, allowing other farmers to offset more of their risks (i.e. growing the economy). Investment companies or hedge funds enter the market purchasing futures, to diversify their risks, allowing them to invest more in equity markets, which fund companies (i.e. growing the economy).
If my point isn't already clear, markets and trading facilitate the diversification and allocation of risk capital to market participants thereby growing the economy. It's the conduit for capital which does make something.
The entirety of your assertion is specious, but there's little value in debating it. The simple fact is that when a user closes their account, they should, at a minimum, be offered the ability to hide their profile from display. Ideally, they would be offered the ability to delete the entirety of their profile data. Facebook, as a company, is effectively stalking every man, woman, and child on the face of this planet. That is not a feature, no matter how much twisted double-speak you employ to justify their actions.
Whether you sympathize with her plight or think she's ridiculous, one important issue remains for all Facebook users. Even if you quit using Facebook, there's no assurance that Facebook will stop collecting data on you, and there's no assurance that Facebook will purge data pertaining to you from their database and website. In fact, it appears that your absence does nothing to curtail their data collection, nor their fictional representation of you. That is extremely problematic. Ideally ending one's account would end the data collection and the data profile. Failing that, at a minimum, one's personal data should no longer be displayed. Unfortunately Facebook's "security" policy seems indifferent to the real-life well-being and personal security of their current and former users.
As a simple example, a farmer hedges his wheat crop selling wheat futures. That allows him to reduce some of his risk, thereby allowing him to plant more (i.e. growing the economy). The market marker who bought the wheat futures may be trading multiple commodities. This trade diversifies his risk, allowing him to trade more of other commodities, allowing other farmers to offset more of their risks (i.e. growing the economy). Investment companies or hedge funds enter the market purchasing futures, to diversify their risks, allowing them to invest more in equity markets, which fund companies (i.e. growing the economy).
If my point isn't already clear, markets and trading facilitate the diversification and allocation of risk capital to market participants thereby growing the economy. It's the conduit for capital which does make something.