Sorry if I did not express myself clearly. "May easily diverge" = "Is guaranteed to diverge at some point, unless we include measures to prevent it".

Such as the hopelessly idealistic Asimov's Four Laws.
Or a more realistic political system of limiting power.
Neither will last forever (think not next decade but let's say 400 years).

In a summary,

• Humans' and SI's goals will inevitably diverge at some point
• We can delay the inevitable but not prevent it
• We knew it before it even started

The obvious question is then, why start?