I think you're being too defensive, I have no intention to start an argument, and you're getting in a bit of a huff for no reason. I'm simply pointing out it is not accepted by any actual historians that the kilt is an ancient piece of Gaelic dress, and offering the general consensus on how Gaels dressed. If you want to be so abrasive though, I can be more argumentative, but it really isn't my goal. I just don't like the proliferation of the idea that kilts are somehow the 'traditional' dress of Gaels. If you want actual sources though, I recommend Matthew Newsome's 'Inventing Tradition'. Newsome is a prominent historian, and his interest in kilts is very elucidating. He notes the oddity that Scots of certain periods tried, ad try, to ascribe the kilt a more ancient origin to it than it possesses (such as claiming that even as far back as 600 the precursor of the kilt had existed in Ireland).
Some other mentions, if you're really interested and can stop working yourself up needlessly;
The account of the life of Magnus Barelegs describes how he dressed in the fashion of a Hebridean (who were Norse-Gaels). "They went about barelegged having short tunics and also upper garments, and so many men called him 'bareleg' or 'barefoot'." There is no mention of anything remotely resembling a ilt here, but this would describe the leine and brat perfectly. A tunic, worn barelegged, a leine or leint, with an upper garment; the mantle or shoulder cloak, a bratt. This is notable in that the Hebrides are from where the first kilts probably came, from the large heavy cloaks they developed to combat the cold. Any ancient analogues to the kilt are unrelated; we have absolutely no proof any such garment was worn in Ireland or Scotland at all until the late 1500s. We do have extensive proof and references to the leine and bratt, though.
The Rogart shirt found in Scotland, dated to the 14th century, closely resembles a leine, though with strips of cloth stitched together. This is not believed to have been for fashion's sake, but for the sake of keeping costs low (instead of discarding the used cloth remnants, they were stitched together to use them).
H.F. McClintock's Old Irish and Highland Dress. Most key to the argument would be McClintock's own opening;
"As a starting point I cannot do better than take a passage from Professor Macalister’s Muiredach Abbot of Monasterboice, in which he says that in ancient times the two main garments worn by persons of importance in Ireland were a long close-fitting smock, for which the Irish word was leine, and an outer mantle thrown over it which in Irish was called brat. He illustrates this by a quotation from one of the early romances relating to pre-Christian times, “The Wooing of Ferb,” and adds that the general details of this dress lasted right down to the 16th century, instancing Durer’s drawing of “Irish soldiers and poor men” painted in 1521."
The account of Bishop Lesley of Scottish dress includes this in a letter to Rome, in the 1570s (If you're interested, I believe Hurst's 'Documents Of The Catholic Church In Britain Prior To And During The Reformation' includes translations, if you want to go and look for them and peruse volumes...God that name is unwieldy);
"They also made of linen large shirts, with numerous folds and wide sleeves, which flowed broad and loose to their knees. These the rich colored with saffron and others smeared with some grease to preserve them long clean among the toils and exercises of a camp, which they held it of the highest consequence to practice continually."
Scots at Haddington in 1548 are described thusly by the Frenchman Jean de Beaugue, "They wear no clothes except their dyed shirts and a sort of wool mantle of several colors.", and in 1573 Lindsay of Pittscottie describes highlanders as "clothed with a mantle, with a shirt (dyed) saffron after the Irish manner, going barelegged to the knee." Just ten years later, the French king's cosmographer Nicolay describes northern Scots as dressing "like the Irish a large and full shirt, colored with saffron”.
Here's a separate Durer work for reference, Irish soldiers and Gallowglass (who would be Scots or their descendants in Ireland);
On the left you can see the Gallowglass, and not a kilt between them, or anything of the fashion, but you can see long shirts, on the far left is one of them in an acton, the second wears a coat of mail over a leine, there's a man then wearing a fur-trimmed cloak and leine, and two kerns dressed in leine with coats. These depictions are from just a few decades prior to the first mention of the kilt.
It's hardly an isolated matter, either. Here's some 16th century Gaelic soldiers, as depicted by an English artist.
A lot of these are later references, but they illustrate a point. Right up till the first definitive description of a kilt in the very late 16th century, Scots and Irish dressed in the same fashion, and there is not a mention of a kilt anywhere. It is not for sake of argument but of education; the kilt simply is not an ancient piece of clothing, it was an advent of the late medieval. Until then, the Gaelic Scots dressed after the fashion of the Irish. There are variations in dress, but they seem the same. Sometimes mentioned are pleating of the shirt's lower portions, which might give the appearance of a kilt on statuary when it's combined with the belt, but that would not be a kilt, just pleating of the lower part of a single garment, separate from the more commonly decorated cloak or mantle.