The President does not hold the nation's purse strings, Congress does. The President cannot simply unilateraly allocate funds to this disaster. In fact, I understand the $350 million he did pledge was the entire amount previously appropriated by Congress in the budget for all emergency relief (including domestic tornados, hurricanes and earthquakes.) His initial pledges of $15,000 then $35,000 must have been allocations they originally found that could be unsed for foreign relief purposes. I understand that the President's pledge has now been approved by the newly covened Congress.
Detractors of the President's actions lack a fundamental understanding of how our governmental system works.
I think the fact the good Prefessor is a liberal Professor of education, neatly explains that failing.