The simulation uses random utility generators, which sometimes create situations where two candidates are highly similar and thus "partially" clones. The point is to model reality.
Other systems might be slightly better. But Approval Voting is dead simple to explain, and you don't even need new ballot papers compared to plurality.
Consider the example with A, B, and C at the end. It claims that approval voting would probably elect C, but why? If the voters apply perfect strategy, B supporters won't approve C, and B will win. The same is true of range voting, where B supporters will give C a rating of zero.
It does not seem escapable that a majority voter block can dictate their wishes on the whole population by exaggerating their stated preferences.
Borda Count really invites the gaming, though. https://en.wikipedia.org/wiki/Borda_count#Potential_for_tact...