You forgot to add that most Ulster Scots readily left both Ulster and Scotland.
Also, Lowlanders didn't wear kilts and they haven't spoken Gaelic for half a millennium, and they sure didn't speak it in Ulster.
What do they like? Fighting things. The Pashtun of the Anglosphere. Hillbillwali FTW!
I know for my ancestors that they were persecuted and forced to leave their homes in Scotland because their lands were given to another clan, and most of the clan was slaughtered by the prince.
As to kilts and Gaelic... meh. The kilt, while being noted for originating as Highland wear, has become a national dress (dress as in attire, not dress as in "oh, look that guy is wearing a skirt") for Scotland because wearing of the tartan was outlawed. When that was repealed a lot of people took to wearing the kilt as a symbol of national pride. Also, many people identifying as having roots in the ancient Celtic Nations (Welsh, Cornish, Breton) have taking to wearing kilts.
Gaelic, at one point in time, may have been widely spoken through out all of Scotland. It was the official language of the court until it was changed to French to seem more... modern (this was back in the day [which was a tuesday] when the French were deemed cool and hip). Many ancient place names throughout the Highlands and Lowlands are Gaelic. Who cares if Gaelic fell into misuse in the Lowlands due to their geographic location next to England (also, politics)? The fact remains that it was spoken there. Also, shouldn't we be more concerned about the fact that Gaelic is close to being considered a dead language (because it was oppressed, kids actually got beat if they spoke it in school), instead of this person or that person spoke it?
I know that for a long time (and still to this day) there was an animosity between Highlanders and Lowlanders. It was almost like having two nations rolled into one. But they kind of got over that when both the lowlands and the highlands were so heavily oppressed by the English (until today where they have gone back to hating each other, it's what we do best, and also explains why my wife and i fight so much... though there is a certain beauty a very mad Celtic woman possesses, a deadly, deadly beauty).
There used to be a philosophy that it didn't matter if you were a Viking, a Celt, Scottish, French, or what have you (aside from English) if you spoke Gaelic you were accepted as a Gael, and into Gaelic culture. Some people are trying to bring that back by reviving the Gaelic language, because lets face it, cultures are united through a common language (which is probably why Esperanto became such a popular language to use for business seeing as how it is made up of different European languages, making it fairly easy to learn and then communicate).
My sources: I read books that are very obviously biased towards the opinions I hold for the Scottish people, because who cares what the evil, oppressive English have to say about anything?
Note: The above line is sarcasm, because whenever I explain my position on things Scottish I always get asked for sources, and when I site those sources I always get told that they are biased. Well, who doesn't honestly have an opinion that has some bias? And really, who cares what the English have to say*?
*no offense meant to any of our wonderful English members (or those descendants of the English), it was just a joke, so please keep your knickers un-bunched.