I'm afraid this graph doesn't say what you think: it's not about edits but about specific edit methods (probably action=edit and action=submit). The list of wikis is not hardcoded but is just the list of top11 wikis by maximum value reached. If you adapt the URL of the loaded graphs you'll see that Wikidata isn't even in top 30, for instance in this one it's 32nd with a max of 48 vs. a max of 212 for the 10th.

https://graphite.wikimedia.org/render/?title=edit%20submits/hour%20Top%2010%20Wikis%20After%20EN.WP%20-1week&from=-1%20week&width=1024&height=500&until=now&areaMode=none&hideLegend=false&lineWidth=1&lineMode=connected&target=cactiStyle(substr(highestMax(summarize(exclude(reqstats.edits.*.submits,"reqstats.edits.en_wikiped"),"1hour"),40),2,3))

http://ur1.ca/hgf85