***Why is He pleased with some and not others?***
I think it is clear in Scripture that He has mercy on whomever he wills, and he hardens whomever he wills.
So why is that?
So that His purpose of election continues.
And why is that?
Scripture teaches it is a mystery.
Well, thank you for the first direct answer that didn't insist on rephrasing the question.
However, I would note that when the Arminians have given a like response for "Why does one choose and another does not?" we've been told the answer is insufficient.
But that's just an observation.
If scripture teaches that it is a mystery, why do people try to figure it out? How does anyone know if they are correct or not? If it is truly a mystery, then anyone could be correct, or none.