Well, that's the thing. If it's a focus for Diana truthiness then equally it might be a focus for Genocide's hate and fear?
That's been my assumption of the storyline. If you're powerful and skilled enough to use it, you can use it to channel your own divine nature. But that's still a bit of a warp from what it's been in the past, when it was not *a* tool, but specifically Diana's tool; an extension of her will as much as Darkseid's Omega Effect or a GL's light constructs; so symbiotic with her that when she loses faith, it shatters, a physical representation of her mental state; so much a part of her that when it gets stolen, she can locate it simply by concentrating, because it calls to her like a wolf howling for its pack.
Though there's still room to assume that, so far; Diana's flipping her shit ever since she lost the lasso - she basically resorts to torture in the current issue in order to get the location of the Society out of Cheetah - which could be pretty easily ascribed to the idea that her lasso is embedded in Genocide's body and therefore its corruption is affecting her, even from a distance.
Same reason Clark shouldn't be able to out-speed Wally?
Yeah, but that's an objective measure. You can look at that and flat-out say "Wally wouldn't have been able to do this;" with a plan of attack, you can always say "Well, yes, that was quite smart, but Batman would have thought of something even smarter," because there's no real way to measure what plan someone *might* have come up with.
Which just makes me wish even more that he'd never been made part of the league.