What is the root of this custom? Well it is simple really. If you are proud of something, you flaunt it, carry it around, show it off by carrying it around on yourself, wearing it. A rare and expensive item of clothing or jewelry or a rare and expensive gadget thus become status symbols, which distinguish you from the crowd. This is the ultimate example of a something that you carry around to show off: an engagement ring. I got him, I won...
If you are a soldier, you proudly wear uniform of your army and insignia of your unit and the flag of your clan, tribe or country. You proudly carry a good and expensive sword which is not easy to get by and you carry the heads or scalps of the dead enemies that you have killed using that sword or a medal saying that you have killed many enemies (much more practical). And you get to be carried on your comrade's shoulders:
If you are a sportsman you carry a laurel wreath on your head that says you were victorious or a medal or a trophy in a shape of cup or plate. You proudly wrap yourself in the flag of your country and carry it around. And you get to be carried on your supporter's shoulders:
If you are proud of a person, you carry him around on your shoulder. This was a treatment which is reserved for heroes and champions. Having a hero or a champion as a member of your family, clan or tribe becomes a status symbol which makes the family, clan or tribe look good. And what do you do with a status symbol? You carry it around, show it off by carrying it around.
In Serbian and in other South Slavic languages, the word for "to carry, to wear" is "nos". The word "nositi" means "to carry, to wear", "prinos = pri + nos = towards, to us + brings" means yield, "odnos = od + nos = from + brings" means relationship and so on. There is a whole cluster of words built around the root "nos" meaning to carry. And believe or not one of those words is the word for pride: "ponos = po + nos" which literally means "something you carry on yourself, something you flaunt, something you carry with you to show off"...
So the people above lifted and carried their political candidate, champion, warrior on their shoulders (po nos), because they, by getting elected, winning championship, killing enemies, became something to be proud of and because of that, something that you can carry around with pride (ponos) because it makes you look good to because you are part of the winning team, army, family, clan, tribe....
Cool, don't you think?
Have a look at another Serbian word built using the root "nos" to carry. The word "nošnja" means costume, traditional dress, something you carry on yourself to mark yourself as a member of a family, clan, tribe. The traditional dress conveys the customs, manners and style of the tribe. It says this is "us" and we are proud of who "we" are. The most visible part of the traditional dress was always the head dress. No wonder then that caps, hats, helmets, hairstyles, feather dress were often used as symbols of identity which were worn (nos) as sign of clan, tribe, national pride (ponos).
Here as some examples of what I am talking about:
Six nations feather gear:
There are many more examples of traditional clothing items which were used as a distinguishing marks and were worn to show pride of being part of a group. This custom of wearing what you are proud of is very strong even today.
Wearing a football jersey or scarf of the football team you support is just such an example of carrying (nos) of what you are proud of (ponos).
The same goes for the GAA (Gaelic athletic association). Here the link between belonging to the old tribal supporter group and the new sports team supporter group is clearly visible. The teams are actually linked to a village (clan) and county (tribe) and the players still play dressed in tribal colors wearing tribal crests while the old war flags of their tribes (counties) are waving in the wind.
If you are a member of a church or a cult, you proudly wear the symbol of your church to show everyone that you are a believer:
If you are a member of a political party, you proudly wear the symbols of the party to show that you belong to it and that you share their ideas:
We wear (carry on our self) what we are proud of. And this link is preserved in South Slavic languages through the words "nos" meaning "to carry, to wear" and "ponos" meaning "pride" but literally meaning "to carry, wear on yourself".
Now what is interesting is that in Irish the word "nós", from old Irish "nós", means custom; manner, style, tradition, fame, renown...