it is worth noting that the reaction didn't come directly from Tzu Chi, but from the HCU's Bhikkhuni Zhao-hui (昭慧法師).
Zhao-hui was known for her social activism within the Taiwanese Buddhism community. She was in support for equal marriage rights, protection of the environment, and women's rights. She was well known for asking for equal rights for Bhikkhuni (female Buddhist monks) and asked for the abolishment of enforcing the eight garudhammas.
Zhao-hui felt like Tzu-chi was unfairly portrayed by Ko and the media, and knew that Tzu-chi would not defend itself through the news media, so she stepped forward.
In hind-sight, she made a wrong move and her choice of words made things worse for Tzu-chi.
I'm curious to if the land was in fact a part of the nature preservation, why did the government allow it to be land filled and sold in the first place. Looking through some online sources, the root cause was that in 1974, Cixin Farmland Irrigation Association questionably sold off that piece of land for people to build high raise housing. When that was blocked, the land became an illegal landfill. When Tzu-chi bought the land under the pretence that was a piece of usable land (they were told by city government employees), the organization became a victim of the Irrigation Association's money making scheme.
That said, two wrongs don't make a right, and that land should not be developed. That's why the insistence of Tzu-chi to develop the land and the choice of Zhao-hui's harsh words are a bit odd. For someone who so defended the protection of the environment in the past, Zhao-hui's latest defiance is a bit of a disappointment.
However, such a straight forward matter has became an outlet for religious slandering. The internet is truly a double edged sword.