Are you actually a scotsman? I am actually a scot. I was born in Glasgow. Are you a true scot like me, or a faker?
Why don't true Scotsmen capitalize "scotsman" or "scot?"

LOL. No idea!
Got it. I think it's because Scotland is the country and can be capitalized, but scotsmen are just the inhabitants.
I think it is because Scottish people hold onto strong tradition, often though they don't know why.
American law comes from and was born out of UK law, which was born out of all kinds of other law back to the Romans.
Capitalization of a personal name takes legal strength away from a person. It turns him into a lesser, or fictional-ish man. Scots are traditionally hanging onto the understanding of this even though government is trying to weed it out of peoples' thinking. Scots always were a legally practical people.
Consider this from
http://www.broadmind.org/:
CAPITALIZE: adj.: Gage Canadian Dictionary 1983 § 4
1. "To take advantage of - To use to ones own advantage."
john doe: a person who is his own master, (sui juris)
Blacks Law Dictionary 4TH ed. (1968) pg. (provides a more comprehensive definition as follows)
CAPITIS DIMINUTIO: (meaning the diminishing of status through the use of capitalization) In Roman law.
A diminishing or abridgment of personality; a loss or curtailment of a man's status or aggregate of legal attributes and qualifications.
CAPITIS DIMINUTIO MINIMA (meaning a minimum loss of status through the use of capitalization, e.g. John Doe) - The lowest or least comprehensive degree of loss of status.
This occurred where a man's family relations alone were changed.
It happened upon the arrogation [pride] of a person who had been his own master, (sui juris,) [of his own right, not under any legal disability] or upon the emancipation of one who had been under the patria potestas.
[Parental authority] It left the rights of liberty and citizenship unaltered.
See: Inst. 1, 16, pr.; 1, 2, 3; Dig. 4, 5, 11; Mackeld.
Rom.Law, 144.
CAPITIS DIMINUTIO MEDIA (meaning a medium loss of status through the use of capitalization, e.g. John DOE) - A lessor or medium loss of status.
This occurred where a man loses his rights of citizenship, but without losing his liberty.
It carried away also the family rights.
CAPITIS DIMINUTIO MAXIMA (meaning a maximum loss of status through the use of capitalization, e.g. JOHN DOE or DOE JOHN) - The highest or most comprehensive loss of status.
This occurred when a man's condition was changed from one of freedom to one of bondage, when he became a slave.
It swept away with it all rights of citizenship and all family rights.
CAPITAL CRIME: The term capital originates from the Latin capitalis, literally "regarding the head".
Hence a capital crime was originally one punished by severing the head from the body.
Capital punishment, the death penalty, or execution is the sentence of death upon a person by the state as a punishment for an offense. Crimes that can result in a death penalty are known as capital crimes or capital offenses.
The simple use of the pronoun "I" can be a great example. The lower case form ( i ) is a man with his head. Capitalizing the "I" shows the man after he has lost his head. Take a look at them together - i I.
Scots aren't as backwards as some people might think. And actually, in many things, it's the other way around even though most people, including most Scots, don't know the whys and the wherefores.
