You're not making their work illegal, you're making the monetization strategy illegal. They don't need to communicate via WhatsApp, they just need to come up with a business model that abides by the terms of copyright law. The problem isn't the business, the problem is the monetization. Facebook is evil because the way they make money is by selling access to their users. There has been no enforcement as to what their users own and what Facebook owns. Change the strategy from "sell our users' data for whatever we can get" to "sell our users' data for an acceptable profit margin because we now have to pay our users" and everything else takes care of itself. No "million little bad decisions" here - Facebook makes more money for better-targeted advertising and there is ZERO cost for increased targeting. Change that cost from "zero" to "anything" and suddenly there's a whole new business model.