Quantum foam ruled out by distant quasars

[windy miller]

In this paper https://arxiv.org/pdf/1108.6005.pdf
It is claimed that
'Our results indicate that most of the models of space-time foam consistent with the holographic principle and, consequently, with black hole entropy, can be ruled out for most of the values of the fluctuation amplitude parameter a0. '
But i find it hard to believe that models like string theory and loop quantum gravity have been ruled out. We should surely know about that if it had happened. So what are they referring to? Can anyone elaborate?

 

[Chronos]

The paper has constructed an intractable logic puzzle. Under results, it is asserted “By adopting the most conservative approach where the correction terms, that describe the possibility for space-time fluctuations cumulating [sic] across long distances and partially compensate for the effects of the phase variations, are taken into account.” We exclude the random walk model and most of the holographic models of the space-time foam” [For sake of brevity, let's just call, 'correction factors' a pink dog. and 'random walk & holographic models' fleas]. This is followed by the assertion “Without considering these correction terms [aka pink dogs], all the main QG scenarios are excluded.“ Let's call 'the main QG scenarios' a collar. Assuming my recollection of logic is sound; if a pink dog has no fleas, and a not pink dog has no collar, what color is a dog with a collar?

 

[windy miller]

The paper has constructed an intractable logic puzzle. Under results, it is asserted “By adopting the most conservative approach where the correction terms, that describe the possibility for space-time fluctuations cumulating [sic] across long distances and partially compensate for the effects of the phase variations, are taken into account.” We exclude the random walk model and most of the holographic models of the space-time foam” [For sake of brevity, let's just call, 'correction factors' a pink dog. and 'random walk & holographic models' fleas]. This is followed by the assertion “Without considering these correction terms [aka pink dogs], all the main QG scenarios are excluded.“ Let's call 'the main QG scenarios' a collar. Assuming my recollection of logic is sound; if a pink dog has no fleas, and a not pink dog has no collar, what color is a dog with a collar?

Thans for your answer. I am not sure I fully understood what you are getting at. but maybe I should ask this question do the main quantum gravity theories predict this effect or not?