The reason is simple: these images require almost no explanation.
A person sees the photograph.
They recognize the resemblance.
They react.
They share it.
The entire experience can happen in seconds.
Posts involving familiar celebrities also have a built-in advantage. Viewers already have an emotional connection to the subject.
Michael Jackson remains a globally recognizable figure, so an image that appears to show him—or someone very similar to him—immediately gives people something to discuss.
The mystery adds another layer.
Who is the man?
Does he know he resembles Jackson?
Was the resemblance obvious to the passenger who took the picture?
Is he an impersonator?
Was it simply a coincidence?
Questions like these encourage comments even when definitive answers are unavailable.
Then humor takes over.
One person jokes that Jackson is secretly living in Mexico.
Another adds a fictional explanation.
Someone else shares the photograph without explaining that the original comment was a joke.