Yeah I posted in there a few times and I disagreed with a lot of what was said there.
My stance is that damaging effects have a keyword applied to them in the description or they are untyped.
"10 damage + 5 poison damage + ongoing 5 damage"
The 10 damage is untyped damage, the 5 poison damage is poison, and the ongoing 5 damage is untyped.
This is correct.
If a poison power did that, it would be as you describe.
It would be:
A poison effect that deals 10 untyped damage, 5 poison damage, 5 untyped ongoing damage.
Poison immunity only affects the 5 poison damage, however, other game rules differ. A dwarf's save bonus vs poison applies to the untyped ongoing damage because while it lacks a damage type, the power that created it has the poison keyword and it is still a poison effect.
I just think that it's odd that immunity isn't more clearly clarified as it can have a significant effect on combat.
It's pretty damn explicit in how it works these days.
If it's immunity to a damage type, you take no damage of that type.
If it's immunity to a condition, you never suffer from that condition.
If it's immunity to fear, poison, charm, polymorph, sleep (I'm sure I'm missing one), you never suffer non-damaging effects from effects with that keyword.
If it's immunity to gaze, powers with that keyword do nothing to you.
That's pretty damn specific. Poison is both a damage type, and has a seperate case explicitly spelled out for it. So that's why immunity to poison gets to do more.