I agree with your observation but Jon Skeet's essay seemed to be focusing on something else... the culture of hostility (or perceived hostility). The key words I noticed he used (multiple times) were "hostility", "jerks", "feelings".
On the other hand, the keywords I would associate with your observation would be... "boredom", "novelty of a new website", "low hanging fruit to quickly build easy karma", etc.
To discuss Jon's specific angle, let's use an example of a [tag] that's fairly new technology such as "[vue.js]". Since Vue is 2014, it doesn't have the "completeness of answers" of a very old tag like C# from 2008.
Here's a Vue question sitting downvoted to negative 4: https://stackoverflow.com/questions/49345098/how-to-get-prop...
Maybe his question deserved all those downvotes. I don't know enough about Vue to guess if the downvotes were all caused by a pasted screenshot instead of pure text.
To Jon's "culture" essay, is the minus-4 the optimal way to communicate it's a "bad" question? Is it a bad question because of its format (the screenshot) or was it bad because "props" is a trivial LMGTFY (Let Me Google That For You Question)?
Here's another Vue question at negative 1: https://stackoverflow.com/questions/49321665/how-to-add-a-ge...
To generalize, if there's "[new technology]" that opens a vast untaken area for new contributions of answers, is the culture created by Stackoverflow's mechanisms (the downvotes, the karma system, the moderators' powers, the "closings" vs "moving", etc) ... the best incentive system to minimize hostility?
Are Jon's well-intentioned "covenants" realistic? Or are they naive to human tendencies when any website is open to mass participation?