No! It is perfectly reasonable for an economist to donate
money to the poor. The discussion in the text was referring
to an illegitimate application of economic theory. Specifically,
some people learn the "law of diminishing marginal utility"
in standard economics courses, and then falsely conclude that
a dollar confers less utility on a rich man than on a poor man.
This talk is meaningless; economics says no such thing. Now if
we want to justify charity on the grounds of moral obligation,
that is consistent with economics. The only point here is that
standard utility theory does not justify wealth redistribution
the way many people think it does.