I assume this is referring to the American Red Cross, because that is where Cracked.com is based. Note also that describing the Red Cross as "a business" is somewhat misleading. It is a foundation.
Red Cross do sell blood to hospitals.
Yes. All the centers that supply blood for transfusions—whether they're part of the American Red Cross or not—sell their products to cover operating expenses. Local hospitals work out contracts with regional suppliers or their local Red Cross facility. [...] All blood suppliers are nonprofits, and the prices they charge follow the cost of production.
This is not a secret, or if it is, it is a badly kept one! The American Red Cross finances are published. The 2014 audited financial statements gives a peek into their operations:
In the 2014 financial year, they made $1.89 billion revenue from "Products and Services: Biomedical", down slightly from $2.04 billion in 2013. [Note: The figures are in thousands of US dollars, so, for example, '1,889,790' corresponds to $1.89 billion.]
It seems the $2.1 billion figure quoted is approximately correct.
Sounds like a lot of revenue, but it is expensive to collect and distribute blood. How expensive? Look at the operating expenses:
Biomedical services cost $1.98 billion in operating costs in 2014. This was not a source of profits in that year.
Like many viral infographics, this one gives one large figure that sounds scary, but nothing to compare it to. The figure is approximately right, but put into context, it is not as disturbing, and paints the American Red Cross in a better light.