I'm curious about what makes this implementation faster than the alternatives.
Also, if you care about function call performance, I guess you'd use PyPy. Have you tried to run the benchmarks (with appropriate warmup) on PyPy to see if the results carry over?
It's possible to maintain the "eclasses" without additional theoretical overhead.
Associate a linked list with each representative, initially only containing the representative itself.
When you union two representatives, concatenate their linked lists in constant time.
In Go, the select branch to take is non-deterministically chosen from the set of enabled branches.
For the examples I don't think it makes a difference, but in general you cannot assume that a select attempts to choose branches from top to bottom.
This one [1] doesn't specifically mention facebook.
You can run the text through a translator yourself, but the main quote: "Henover weekenden har vi allerede set de første eksempler på danskere, der sælger QR-koder i lukkede grupper på sociale medier" roughly translates to: "During the weekend we have experienced the first examples of people selling QR codes in closed groups on social media".
Edit:
This article [2] is about 6 teens being charged with forgery of the pass.