Estimation is the best we have
This argument seems common to many debates:
‘Proposal P arrogantly assumes that it is possible to measure X, when really
X is hard to measure and perhaps even changes depending on other factors.
Therefore we shouldn’t do P’.
This could make sense if X wasn’t especially integral to the goal. For
instance if the proposal were to measure short distances by triangulation
with nearby objects, a reasonable criticism would be that the angles are hard
to measure, relative to measuring the distance directly. But this argument is
commonly used in situations where optimizing X is the whole point of the
activity, or a large part of it.