Well, Aman, seems like you brought up the sentence from Guardian (from the link embedded in/inside the post), so would be more like "British Grammar", hence the link I posted before was focused in that kind of English.

     Anyway, see the boldened part, fell that in English what matters is not the tense in itself but its effect (or, say, after-effect).    The "present" in the "present perfect simple " is the "remindind" of this effect in the present.

    Now, not having the "signal words'' you are used to see in English lessons, it´s an incentive to see the sentence from others perspectives; and to see the emphasis is seems like one that figures first in the "peck order" of the list, hence I let then in blue and boldened.

http://www.ego4u.com/en/cram-up/grammar/simpas-preper

Use:
     In British English, the use of Simple Past and Present Perfect is quite strict. As soon as a time expression in the past is given, you have to use Simple Past. If there are no signal words, you must decide if we just talk about an action in the past or if its  consequence in the present is important.
     Note that the following explanations and exercises refer to British English only. In American English, you can normally use Simple Past instead of Present Perfect. We cannot accept this in our exercises, however, as this would lead to confusions amongst those who have to learn the differences.

http://www.ego4u.com/en/cram-up/grammar/simple-past
    Use of Simple Past

action in the past taking place once, never or several times.
Example: He visited his parents every weekend.

actions in the past taking place one after the other
Example: He came in, took off his coat and sat down.

action in the past taking place in the middle of another action
Example: When I was having breakfast, the phone suddenly rang.

"if" sentences type II (If I talked, …)
Example: If I had a lot of money, I would share it with you.

Signal Words of Simple Past
yesterday, 2 minutes ago, in 1990, the other day, last Friday
If-Sent Typ II (If I talked, …)

http://www.ego4u.com/en/cram-up/grammar/present-perfect-simple
Use of Present Perfect
puts emphasis on the result
Example: She has written five letters.

action that is still going on
Example: School has not started yet.

action that stopped recently
Example: She has cooked dinner.

finished action that has an influence on the present
Example: I have lost my key.

action that has taken place once, never or several times before the moment of speaking
Example: I have never been to Australia.

Signal Words of Present Perfect
already, ever, just, never, not yet, so far, till now, up to now
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    And,  LAST NIGHT is normally used in the SIMPLE PAST.  

    http://www.colegioweb.com.br/ingles/simple-past.html
Os verbos no SIMPLE PAST são empregados para indicar uma ação completamente terminada no passado ou uma ocorrência habitual de ações no passado.

Orações no simple past são normalmente acompanhadas por advérbios ou locuções adverbiais que indicam tempo passado, como: yesterday, last + advérbio de tempo (last night, last month, last year) e expressões compostas por advérbio de tempo + ago (a year ago, a few hours ago, a month ago). Pode aparecer também após alguns advérbios que funcionam como indicadores do SIMPLE PRESENT (always, never, on weekends), mas para indicar uma ocorrência habitual no passado.