Well, more specifically, I pointed out that the Energy Aura critter power never says that it deals damage to things that the critter is just touching. The power gives two instances where it deals damage: when the critter is attacked, and when the critter is attacking.
So in the case of spirits, they always have the aura. This means that they potentially have a visible effect going on around them all the time. It also means that if they ever get attacked, it will damage the person who attacks them. It also means that their natural attacks will also deal additional elemental damage. None of those things can be stopped, the power is always active.
But a lot of people seem to think that the Energy Aura power means that the critter would be haphazardly laying waste to its surroundings all the time. For instance, I've seen people saying that a Fire Spirit would just light objects on fire by its mere presence. The power never says that it does something like this, and if it did, it would probably say something about a range that the aura effects, or mention that contact with the critter's body would have some sort of effect. It never mentions either of these things, so it doesn't do any of those things.
TLDR, the spirit doesn't get to choose if it applies the damage from its aura. If it attacks, the aura applies, and if it is attacked the aura lashes back. But those are the only times that a spirit's energy aura does anything dangerous, so it would otherwise be safe to just have around.