Because he was being snarky while adding nothing to the discussion.
"Because China has a wonderful record on industrial pollution"
And this will affect the financial success of the project how? Grandparent's point was that technological advances since Panama Canal will make the project more cost effective.
"and Central America has a wonderful record on fiscal responsibility and accountable government."
Except it's the Chinese footing the bill and making the decisions, so this comment is irrelevant.
He's just pandering to Slashdot groupthink and bashing China pollution and Latin American corruption. And it worked too, currently at +5 insightful.