Once you learn that they are selling ads on websites, "what does the company do to earn money" seems to be sufficiently answered.

Also I would strongly suspect that most traders of stolen goods (ad spots, in this case) would have a path for legitimately acquired merchandise as well, not only for plausible deniability but also because they sure would not mind paying their bills in a clean way, they just failed to resist the lure of the extra cash. With that in place, you'd have to actually work in the shady part to know about it, or have bird's eye numbers of the whole company where you might see that output does not match the legitimate input.

"It is difficult to get a man to understand something, when his salary depends upon his not understanding it!" --Upton Sinclair

I really think this quote is a bit unfair here. Especially in the startup scene, many companies have quite vague product descriptions. I've worked at a place where it took me 3 months to figure out what they were doing (nothing immoral BTW, just very complex/diverse products).

But for those three months you had no idea whether what they were doing was moral or not, and you didn't check.

A nice tech jobs in a cushy air-conditioned office that lets you feed your family: Jobs like these don't grow on trees.

I used to work for a residential Real Estate platform, as a network/server OS/hardware worker. I didn't realize I had been hired by email spammers until we got Spamhaus emails, and my job became getting us off the RBLs.

Years ago I worked at a place where I didn't know what the company did. I knew they made physical products (had a factory in the building) that had some sort of industrial use. However I didn't have the very specific domain knowledge to understand what those products did and my job didn't depend on it. My team was the only software team not writing firmware - we worked on the intranet. It didn't help that all conversations were filled with jargon.

I got the impression it's just super fun. We're doing ad syndication! We sell space on websites! We have an innovative peer disruption space sorting alorithm optimizer!

I have a colleague you might like to meet. Understanding anything is not his forté. He turns up, does what he is told, goes home, and is paid at then end of the month. Except maybe the "does what he is told" part, but that is a different story!