For one, pretty much every example cited in the article are "clones" of products that the "aggrieved" party was also giving away for free. But let's ignore that.

Let's take Stories. Facebook has monetized them, and pretty clearly realized they could monetize them when they rolled out. Does the fact that Snapchat came up with them mean Facebook should not be able to launch something that they plan to monetize? By this logic, anything Facebook rolls out that someone else did first wouldn't be allowed.