the club have just emailed season ticket holders to invite them to the kit launch at institution bar in Palmyra square next Wednesday evening.. with a shot of the sleeve of the kit - which is blue

I’m not sure blending in is quite the same issue as in football. Hardly looking to spot a man 50 metres away to pass to, forward, sideways (or even backwards). Most passes are relatively short, and long kicks are into space* (hopefully).
* “space” as in unoccupied rather than “outer”.
As for the sizing of shirts, as long as it fits does it matter what the size actually says?

Size does matter.

Maybe so, but if it is called xl but in reality it is an M that doesn't affect the actual size...

I sold the dprl shirt on because the xl went nowhere near me.

Never had an issue with O'Neills Sizes, that includes all the GAA and Amateur RL gear I own.

Maybe some people are just an awkward shape?