Using the present perfect or the past simple when referring to a deceased subject?

Question

If there has ever been a man who has been faced with challenges of opposition both at home and away, then it is King David. First of all his father completely forgot about him when a prophet came calling at their house and enquired of him. Later he was asked to go home and tend to sheep by his brothers when he went to visit them on a battlefield. Then he had to kill a giant to prove he was not a dog like he was referred to. He later had to flee his home because his father in-law, King Saul wanted to kill him.There are people like that in the world of work too. [...]

Source: hrfocusuniverse.com

If there has ever been a man who has been able to change the destiny of millions, it is none other than Prophet Muhammad (peace be upon him), the last prophet of Allah (God for some). Michael H. Hart, who wrote the book ‘100 most influential people in the world‘ in 1978, lists Prophet Muhammad at the top of his list because according to him Prophet Muhammad had done the most to influence the world.

Source: myultimatedecision.info

Trump tried to pass a real infrastructure bill for two years. And if there has ever been anyone who has been president in the history of this nation who knew more about infrastructure than Trump I cannot imagine who it might be. Eisenhower, maybe? Maybe?

Source: acecomments.mu.nu

What does the present perfect convey in these sentences that the past simple doesn't? If someone could explain to me, why would the authors of these excerpts prefer the present perfect over the past simple?

I would expect to read "If there has ever been a man / anyone who was"... rather then 'has been' when it comes to referring to someone who doesn't exist anymore.

Answer 1

The reason for this, I presume, is because that the deceased person (bar case three, which is not exactly the same reason as the other two) continues to be the only man that did or was known for something, in your examples sentences. For example, in example number one,

If there has ever been a man who has been faced with challenges of opposition both at home and away, then it is King David. ...

The "something" is "faced with challenges of opposition both at home and away" here, and the person is King David. Since this sentence claims that the person (King David) is the only person in history (as is meant by "If there has ever been") that have been "faced with challenges of opposition both at home and away", it means that this event/statement still holds true to this day. This is exactly the correct usage of the present perfect tense^[1][2]. Present perfect tense are used to describe "An action or situation that started in the past and continues in the present." This sentence perfectly matches this definition. The second example also have a similar construction:

If there has ever been a man who has been able to change the destiny of millions, it is none other than Prophet Muhammad (peace be upon him), the last prophet of Allah (God for some). ...

Thus, this sentence works the same way as in the first.

Finally, the last example:

... And if there has ever been anyone who has been president in the history of this nation who knew more about infrastructure than Trump I cannot imagine who it might be.

This one is a bit different. The person in question (President Trump) is certainly still alive, so this shouldn't fall into the "deceased people" example list. Also, the situation described is also (according to the source) still ongoing (i.e., Trump is still the president who knew about infrastructure more than any other presidents; this is a bit political though), thus the sentence is correct. In any case, all three sentences could and should use the present perfect tense.

Answer 2

Consider:

(1) There has never been a man who has been foo.

This may be somewhat inelegant (it would be more natural to say 'no man has ever been foo'), but that is not relevant to the question (what makes it inelegant is the presence of two has beens, but that is something that it shares with the examples in the question). A lot of philosophical literature is devoted analysing such sentences, that are purportedly about something non-existent, but even without going into these discussions, we can see that this sentence is not about any particular man. From that it follows that we can't even ask whether the man that the sentence is about is living or deceased.

Now consider:

(2) If there has ever been a man who has been foo, that man must have also been bar.

The man in this sentence functions the same way as man in (1): it does not stand for any particular man, living or deceased. The sentence leaves open the possibility that such a man might have existed, but does not commit itself as to his existence.

The first part of (2) (the antecedent of the hypothetical) is the same as the first part of:

(3) If there has ever been a man who has been foo, that man is King David.

The second part of this sentence is about a specific man, but that in no way changes the fact that the first part is not about any particular man, just like the first part of (2) is not about any particular man.

The question is thus based on the mistaken assumption that the subject of the instances of has been that are bolded in the question is the same person as is referred to later in the quoted texts.