[@Jbcool] Yes, no reason;
The eldar don't like chaos, sure. They Never actively seek out combat with them, unless 100% necessary. Even then, they prefer sending other factions to fight them. In fact, Eldar hardly ever engage in combat, period. They don't want to risk their own, far more valuable, lives on anything they don't have to. The spirit stones being on that ship is, already, a heavy-handed excuse for them being here to begin with.

Speaking of the ship... if that's the reason they're coming, then they would have already. If they're actively looking for Urgrugg, he's not going to stay hidden from them. Eldar psykers are far too good at what they do for Urgrugg's passive defenses to keep him hidden from them. If they actually know he was on the ship, and are looking for him because of it, then they'd be on their way already. If anything, him summoning daemons would be a deterrent, because they wouldn't be quick enough to stop him, and additional forces means additional resistance.

So, yes, no reason. They want the ship, not him. They don't like chaos, but they care far more about the lives of their own then sending a scant dozen or so daemons back to the warp. If they're coming after him because of the ship, they're already on their way anyway, and would probably just grab it off the hull and leave instead of engaging, and would be More likely to do so if daemons are being summoned.