Actually, Kerry's colours look much more like green and yellow. I can see where you're coming from with Antrim though!
I agree with you about the yellow, but the GAA and sports commentators still refer to it as "gold", which it is clearly not.
Actually, it is gold. The Kerry colours were adopted (in the late nineteenth centrury) by a resolution of the County Board which specified “green and gold”. They are probably taken inspired by the arms of the Kerry County Council which shows, among other things, a crown against a green background. While the crown is in practice coloured yellow or orange, since crowns are typically made out of precious metal rather than fruit naming the colour as “gold” is probably permissible artistic licence.
We also have to remember that in the nineteenth century true gold fabric dye did not exist, so any county adopting “gold” as one of its colours knew that it would be represented on jerseys with some version of yellow or orange. Quite a number of counties adopted gold – apart from Kerry, I can think of Leitrim, Meath, Wexford and Tipperary; there are probably more. Clare and Antrim adopted “saffron”, a colour with a Celtic-romantic association with the ancient Irish, who were often described as wearing saffron-coloured clothing (probably because a saffron colour was one of the few permanent dyes they could make). Roscommon adopted “primrose” – God knows why – Kilkenny “amber” and Carlow “yellow”. Only Armagh adopted “orange”.
It’s a mistake to think that any yellow or green/yellow combination in GAA colours is a reference to the national flag. The county colours were mostly adopted well before the tricolour became the dominant national (or nationalist) symbol, and generally find their inspiration elsewhere. I don't know what inspired Armagh's choice of orange, but it strikes me that it probably wasn't a reference to the loyalist tradition.