How do I know if I need a transit visa when the ticket is purchased online?

Some countries had weird rules, like Saudi Arabia. Recently, I purchased a tick to the US from Pakistan with a layover in Saudi Arabia. On the way out, it was a 11:30-hour layover and I had no issue. On the return flight, the layover was over 12 hours, hence supposedly I needed a transit visa for that.

To make things even worse, being a female passenger alone, Saudi Arabia does not issue transit visas to females alone, and even worse, they do not issue transit visas at all in the Hajj season, which is currently going on.

The problem is, it gets very complicated to find if you need a transit visa. The ticket does not say so. Further, visa requirements for each country are different. As as a side note, Internationally famous Pakistani Singer was deported from India (Hayderabad), just because Pakistani citizen cannot enter India via Hyderabad, which he learned the hard way after arriving in Hayderabad

In this case, we could have googled and found out but it was too late. Our return ticket could not be used and we had to buy another, more expensive, ticket. So my question is, isn't there any requirement for airlines (or ticket issuing authorities) to inform customers if they need a visa? With all the computerization and where every plan can be tracked online, I think this is not a difficult thing to do.

If every person starts calling the airline about their transit visa requirements, obviously call centers will be bombarded with calls, not to mention that in this case we called Saudi Airlines for support and no one bothered to pick up the phone in Islamabad and Peshawar (Pakistan). So in this technologically advanced world, the passenger is at the mercy of last-minute counter decisions. "Sorry, you can't board the plane because you don't have a visa". That information surely could have been communicated well in advance, when issuing the ticket.