"Flee if pushed to pay". This uses a very narrow definition of pay. The reach into your pocket to pay cash that you earned. But there are other ways to pay - ie with something else of value to you (time/attention), your vote in an election etc. Remember that Twitter competitor that was a monthly sub with no ads? It made the above mistake - that there was only one honorable way to launch and charge for a service that brings value to millions of people.