My conspiratorial (*completely evidence-free as far as I know) theory on hookup apps is that they're secretly backed by the major pharmaceutical manufacturers of various STD treatments.

The numbers are interesting: there are about 32,000 new HIV cases in the USA each year, and the per-month cost of ongoing anti-retroviral therapy is estimated at $1,800 - $4,500. This works out to a gross cost of ~ $0.7 billion to $1.7 billion - and it's cumulative, year after year. as HIV patients need this treatment for the rest of their lives. Given profit margins of 10-15% in pharma at least, this is a huge cash cow for the industry. (Also explains the reluctance to invest in seeking a permanent cure for the disease that would allow patients to terminate their therapy).

Now, would a profit-hungry industry deliberately encourage reckless sex practices in order to grow demand for their product, year after year? It might bear some investigation.