One does not have to go far back in time to see that the different Arab communities of Palestine had nothing in common with each other, and in fact usually fought with each other.
From The New Werner Twentieth Century Edition of the Encyclopaedia Britannica, entry on Palestine, 1907:
The Arab tribes transplanted to Palestine their old distinctions, especially that between Northern and Southern Arabs (Kais and Yemen; cf. Arabia). The Arab peasantry is still divided into clans; for example, the districts of the Beni Hasan and Beni Malik to the west of Jerusalem, those of the Beni Harith, Beni Zeid, and Beni Murrd to the north, and that of Beni Salim to the east. Till recently the relations of the separate clans of fellahin was one of mutual hostility, and, unhindered by the Turkish Government, they engaged in sanguinary conflicts. In manners and in language (though Arabic is universally in vogue) the Palestine peasants retain much that is ancient. It is extravagant, however, to maintain from the traditions they preserve that primeval Canaanite elements still exist among them. The prevalent type, in fact, is Syro-Arabic, or in many districts pure Arabic; and their superstitious customs are partly remains of Syrian beliefs, partly modern Arabic reproductions, under similar external conditions, of ancient superstitions. These remarks are applicable to the saint worship at present spread through the whole Oriental world. The fellahin are on the whole a diligent frugal race, not destitute of intelligence. If well treated by a just Government which would protect them from the extortions of the nomadic tribes, they would be the means, with the assistance of the capitalists, of greatly improving the cultivation of the country, especially in the various lowland districts. They choose their own village sheiks, who derive most of their authority from the reputation of their virtues, their bravery, and their liberality. The Bedouins, i.e., wandering tribes of pure Arab origin, also play an important part in the country. Till quite recently they used to visit certain settled districts and exact black-mail from the peasants; and they find their undisputed domain in those districts which are incapable of cultivation, and fit only for cattle rearing, and in other fertile portions which for various reasons are not occupied by the husbandman. To the first class belong the belt of desert to the west of the Dead Sea, the southernmost parts of the country west of Jordan and the south country beyond the river (Moab); to the second belong the greater portion of the maritime plain, the depression of the Jordan valley and part of the country to the east. The divisions of the Arab tribes will be discussed in the article Syria. In Palestine east of Jordan the Beni Sakhr (Moab) are of most importance; Jebel 'Ajlun is the seat of the 'Adwan. The Ghawarine (the inhabitants of the Ghor or Jordan depression) form a peculiar race which, as they are partly agricultural, have been a long time settled in the district. In type, as well as by their degeneracy, they are distinguished from the other Bedouins. The true Bedouin style of life can be studied only beyond the Jordan or to the south of Palestine—the tribes west of the river, such as the Ta'Smire and Jehalin in the south being all more or less deteriorated.
The Palestine Exploration Fund in 1884 researched the names of the tribes around Jerusalem and discovered something fascinating:
If, however, we turn to the map of Arabia in the days of Muhammed and of Omar, we find the following tribes represented :—Other more recent scholars concurred - the tribes of Palestine were transplanted splinter tribes from various parts of Arabia and kept their names.
Beni 'Amir, a tribe of the Nejed near Yemana, or again south-east of Medina.
Beni Harith, a tribe of Yemen north-east of Sana.
Beni Murreh, both east of Medina, and south of the Jauf Oasis.
Beni Suleim, east of Medina.
Beni Malik, a division of the Beni Temim, who lived near Yemana.
It was with the aid of these and other tribes that the famous Khaled defeated the Romans on the Hieromax in 634 a.d. ; and under Omar they swept over Palestine soon after.
It seems therefore probable that in these local names we have a trace of Omar's Conquest of Syria, and that the hills of Judea and Samaria were regularly portioned out among his followers. The noble families of Jerusalem still claim to have "come over with the conqueror" at this time. We have thus only another instance of the survival in Syria of early Moslem divisions, and the division of the Keis and Yemeni factions, which dates back to the early days of Islam, is still hardly extinct, and is well remembered in Southern Palestine.
A later work called Syrian Stone-lore, or The Monumental History of Palestine also written for the Palestine Exploration Fund seems to have heavily borrowed from the above quote, but added:
In 1881 I heard related in Taiyibeh (see 'Memoirs,' vol. iii.) a long account of the contests of these factions, occurring in quite recent times. In Palestine the Eastern Arabs were the Yemini party, and the settled village population mainly the Keis party. This feud of Keis and Yemini, which arose when the Ommeiyah ruled Palestine, was a split between the Aramaic or North Arab tribes, who claimed descent from the Adites, and the Yemenites or South Arab tribes, who claimed descent from Himyar and from Kahtan. The two factions were, however, joined by various tribes from purely political motives, so that the division is not exactly one of race. In 64 A.h. Merwan had some tribes of South Arab origin on his side at the battle of Merj Rahif.This is not controversial. The simple fact is that the Arabs of Palestine before 1900 identified fully with their tribes and villages and not at all with each other, and they had no more in common with each other as they had with their neighbors across the Jordan and in Syria.
Saying that they were a "people" is simply fiction. An argument can be made that they are a people today, mostly because of their shared suffering at the hands of their Arab brethren, but before the 20th century it is simply not true.