You nullified nothing, since there was nothing to begin with. You would have nullified the future threat if you manage to stop the Chinese taking over the port altogether. Why don't we expect anything else? Srisena seems to be playing the middle game quite well, he explicitly made sure the Chinese still maintain control of the port. The future militarization burden will not fall on him, it will be others. His immediate problem is the debt.
The so called failed airport could be a Chinese air base in the future. SL do owe us billions afterall.
We play the long term game bro. Djibouti caught US by suprise, but notice how we were there 10 years earlier, building rails, modernizing ports and providing jobs. The Djiboutians see this, the Chinese are not there just for a base, it's more than that.
It all starts with an innocent little port. Do you know the story of Gwadar?