The conclusions he draws aren't that sweeping. He gives specific examples with coordinates and Viking image numbers that appear to show channels on the youngest volcanic flows in Tharsis. No doubt your library carries Icarus. I'd like to hear if he makes different conclusions than what he proposes in the LPI report.
It is common when proposing a theory to collect as much evidence as you can in support of that theory.
It doesn't seem reasonable to me that all these separate lines of evidence that suggest recent or current water/ice near the equator on Mars are all there just because of a coincidence.
One might deny the Athabasca evidence, but then there's the lobate crater evidence of Clifford, independently confirmed by Barlow.
One might not like this, but then there's the anomalously high and diurnally variable water vapor amounts over Tharsis.
Some researchers might not be impressed by this but then there's the GRS data indicating high water/ice/bound water amounts in Tharsis.
Others might not find this compelling, but then there's the recent report suggesting the dark streaks preferentially found in Tharsis occur after above freezing temperatures are reached.
Some might discount this but then
there's the observations of Helgason and recently Head that geomorphology suggests recent and perhaps current glaciers in Tharsis.
And moreover on top of all this there is the data from radar observations from Earth of seasonally variable radar reflectivity in the equatorial region that is consistent with the high radar reflectivity of briny water.
Note that Clifford has already proposed a theory to explain how this water can persist there into the current time. And in
fact the scientists proposing recent water in Athabasca cited Clifford's theory as one possile explanation of the water near the equator there, in addition to the possibility of exchange with the atmosphere. I think they mean rain by this.
BTW if you want some more there have been recent reports that Valles Marineris, also near the equator, currently has ice in the valley walls.

Bob Clark