I think I see what you are saying, though I am not 100%.
With
normal weapons, if you attack, your weapons require repair. If you are defending, your weapons also require repair. You don't actually lose any Actual weapons, unless the defensive power reaches 0 (lose all), or sabotaged (lose some).
With
fleets, if you attack a planet, your fleets require repair, like normal weapons. They also appear in the armoury, with normal weapons. However, when you are attacking or defending, and the enemy MS offensive power, is greater than the defensive power on your MS, you lose whole Fleets, rather than becoming 'damaged', like normal weapons.
In my mind, this is not really a bug. I have always seen 'fleets' as groups of small specilised ships, not escourting.. being MS groupies?
Idk. While your MS is bigger, their planet weapons can provide additional power to the offense of your MS.
Since they have no shielding of their own though, as soon as enemy MS fire breaches your own shielding (usually protecting MS + fleets) they are toast, and die in hoardes.
I do see your point and I will stop waffling
. Since they aren't affected by sabotage, I don't see them as normal weapons.