It's been explained often on this site, and @Peter Shor explains again in his comment, that the present perfect is simply the past with an expectation of more to come.
The present perfect is a grammatical combination of the present tense and the perfect aspect, used to express a past event that has present consequences. The term is used particularly in the context of English grammar, where it refers to forms such as "I have left" and "Sue has died".
In the above example, clearly (I) left in the past, but there is an implication for present day consequences:
I have left, but I will most certainly be back.
I have left, and you'll realize what you've been missing.
Similarly, in your example:
They have done it in the past; there is no reason they cannot do it again.
People often misuse the present perfect for the simple past, and it's understood, though it's less than ideal usage. Sometimes it is used to emphasize that an action has been completed:
I have finished my homework!
But the implication is still there:
I have finished my homework! So stop accusing me of slacking off!