Shorts and a tee shirt should be sufficient; don't you think?

It seems as though whenever I see pictures of folks in the Shuttle or at
Alpha they are always wearing long sleeves and I think long pants, too.
As it is the case that the thermal environment in those two venues is
totally under human control, I don't understand why the setpoint is so low
as to require such heavy clothing. Why not set the temperature at 80F or
so and have the humans wear just shorts and a tee shirt? Why carry bulky
clothes? Do they keep it cold so that the electronics stay cool, or is
there some other technical reason?

I seem to recall that in the High Frontier, O'Neill posits that the first
Island One would have a Hawaiian-type climate. That would seem very
reasonable to me, because otherwise clothes would have to be imported and
maintained. Why doesn't Alpha have an internal environment maintained at
Hawaii temperatures?

Ron Menich