Combining the prayer Sunni vs Shia

In the name of Allah, the most gracious and the most merciful.

Shia make the claim that it is permissible to combine the prayers for no reason.

Is this true or false?

Book 004, Number 1515:

Ibn 'Abbas reported: The Messenger of Allah (may peace be upon him) observed the noon and afternoon prayers together, and the sunset and Isha' prayers together without being in a state of fear or in a state of journey.

Book 004, Number 1516:

Ibn 'Abbas reported: The Messenger of Allah (may peace be upon him) observed the noon and afternoon prayers together in Medina without being in a state of fear or in a state of journey. (Abu Zubair said: I asked Sa'id [one of the narrators] why he did that. He said: I asked Ibn 'Abbas as you have asked me, and he replied that he [the Holy Prophet] wanted that no one among his Ummah should be put to [unnecessary] hardship.)

Book 004, Number 1517:

Ibn 'Abbas reported that the Messenger of Allah (may peace be upon him) combined the prayers as he set on a journey in the expedition to Tabuk. He combined the noon prayer with the afternoon prayer and the sunset prayer with the 'Isha' prayer. Sa'id (one of the rawis) said to Ibn 'Abbas: What prompted him to do this? He said: He wanted that his Ummah should not be put to (unnecessary) hardship.

Book 004, Number 1518:

Mu'adh reported: We set out with the Messenger of Allah (may peace be upon him) on the Tabuk expedition, and he observed the noon and afternoon prayers together and the sunset and 'Isha' prayers together.

Book 004, Number 1519:

Mu'adh b. Jabal reported: The Messenger of Allah (may peace be upon him) combined in the expedition to Tabuk the noon prayer with the afternoon prayer and the sunset prayer with the 'Isha' prayer. He (one of the narrators) said: What prompted him to do that? He (Mu'adh) replied that he (the Holy Prophet) wanted that his Ummah should not be put to (unnecessary) hardship.

Book 004, Number 1520:

Ibn 'Abbas reported that the Messenger of Allah (may peace be upon him) combined the noon prayer with the afternoon prayer and the sunset prayer with the 'Isha' prayer in Medina without being in a state of danger or rainfall. And in the hadith transmitted by Waki' (the words are):" I said to Ibn 'Abbas: What prompted him to do that? He said: So that his (Prophet's) Ummah should not be put to (unnecessary) hardship." And in the hadith transmitted by Mu'awiya (the words are):" It was said to Ibn 'Abbas: What did he intend thereby? He said he wanted that his Ummah should not be put to unnecessary hardship."

Book 004, Number 1521:

Ibn 'Abbas reported: I observed with the Apostle of Allah (may peace be upon him) eight (rak'ahs) in combination, and seven rak'ahs in combination. I (one of the narrators) said: O Abd Sha'tha', I think that he (the Holy Prophet) had delayed the noon prayer and hastened the afternoon prayer, and he delayed the sunset prayer and hastened the 'Isha' prayer. He said: I also think so.

Book 004, Number 1522:

Ibn 'Abbas reported that the Messenger of Allah (may peace be upon him) observed in Medina seven (rak'ahs) and eight (rak'ahs), i. e. (be combined) the noon and afternoon prayers (eight rak'ahs) and the sunset and 'Isha' prayers (seven rak'ahs).

Book 004, Number 1523:

'Abdullah b. Shaqiq reported: Ibn 'Abbas one day addressed us in the afternoon (after the afternoon prayer) till the sun disappeared and the stars appeared, and the people began to say: Prayer, prayer. A person from Banu Tamim came there. He neither slackened nor turned away, but (continued crying): Prayer, prayer. Ibn 'Abbas said: May you be deprived of your mother, do you teach me Sunnah? And then he said: I saw the Messenger of Allah (may peace be upon him) combining the noon and afternoon prayers and the sunset and 'Isha' prayers. 'Abdullah b. Shaqiq said: Some doubt was created in my mind about it. So I came to Abu Huraira and asked him (about it) and he testified his assertion.

Book 004, Number 1524:

'Abdullah b. Shaqiq al-'Uqaili reported: A person said to Ibn 'Abbas (as he delayed the prayer): Prayer. He kept silence. He again said: Prayer. He again kept silence, and he again cried: Prayer. He again kept silence and said: May you be deprived of your mother, do you teach us about prayer? We used to combine two prayers during the life of the Messenger of Allah (may peace be upon him).