I'm sorry; its just how I write here.Bulborb babies, Grubwigs and other enemies who would be in the range of their breath (and are instantly killed if they swallow whites) aren't harmed.
If their breath is identical to the toxins inside them, it isn't deadly or harmful in small amounts.
Also your font is really annoying to read in whiteboards.
Let's look what we have here then, for you make a good point:
When eaten, even by a collossally sized enemy, the poison kills or harms them greatly in an instant. Whether small or large, this toxin is incredibly deadly.
On the other hand, enemies (small) can walk thru the poison breath unharmed, essentially immune to this poison or its amount. You said this was due to the small amount of poison not being enough. However, despite what I said before, this doesn't make sense to me, because those are small enemies that are able to walk thru it unharmed. And yet, when white pikmin are eaten by a HUGE enemy, the proportion of toxins to creature exposed are similar, except that the method of poisoning is different. Despite what my last post said, this leads me to believe that the poisons MAY be different after all....
This could mean two different things. One is that the white pikmin's breath may not be lethal at all, which would mean their weapon against the ICs is useless. The other possibilty is that the enemies that live thru this because they have an immunity against it. This is possible since enemies from the pikmin games have been shown to walk unharmed thru those poison pipes in PIkmin 2; meaning that enemies have some resistance against toxins.
Additionally, its also possible that the white pikmin can emit poison more than they let on. But anyways, if it sthe first choice of that last paragraph, we have lost our best weapon. If its the latter, the Ics may not have the same immunity as the creatures there do, being only human and not evolved around it.
@Joe - those other six are inferior to purple or white pikmin; thats why they haven't been discussed much.
And what a worthy 700th post!