I don't think that any of those explanations are very good. Consider this table of outcomes:
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x x +

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o x +

x o +

x x o

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The first line represents the starting, pre-intial-choice position of goats and car, where 'x's represent goats and the '+' represents the car. Underneath are the choices made. The obvious next step is what door Monty opens, and the obvious solution to this is:
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o X +

X o +

X x o

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Which shows us that it would be positive for us to switch, which seems counterintuitive. However, this is not really correct. The table should be:
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o X +

X o +

X x o

x X o

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Which shows us that switching makes no difference.

The crux of the apparent paradox is that Monty knows which doors hide goats, which means that the last two possibilities collapse into one (like the "incorrect" table), since it is irrelevant to Monty which of those two doors he opens. The problem is that it is not random, despite being presented as such.