After riots if Vietnam government pay for the damage cost for all companies & factories, it will be lots of money and increases another financial burden for VN government, at last these money come from normal Vietnamese ppl's tax.
If Vietnam government won't pay for damages, many foreign companies & factories lost productions and equipments in this riots, even whole factory buildings burnt out by mobs. Most of them will bankrupt or lost their investments in Vietnam, even did not attacked by mobs but the factory shut down also lead to financial loss. Many Vietnamese workers also losing their jobs together, decrease "Made in Vietnam" export in 2014.
It doesn't matter what Vietnamese anti-China riots going on, it did not hurt China economy anymore. They just were destroying foreign investments and private companies & factories. For foreign investment, they need a safe environment to earn money not in a chaos political society, if not why not invest Somali where has cheaper workers ? The damaged companies & factories might shut down and dismiss local Vietnamese workers, the rest might consider withdraw capital to take care their money, move to other more security SEA nations.
Playing FIRE in ur house, at last burn urself ***.