Apparently, they planned to move away from this in May (last month), but the text is still in past tense, so I have no idea if this ever happened.
At that time, some random numbers were sampled (which we refer to as the “toxic waste”) and were then used to construct the parameters.
After the setup phase, the toxic waste had to be destroyed to prevent counterfeiting of Zcash.
That was at the beginning. But the recent network upgrade has changed all of that (apparently) by removing the trusted setup. Some said Zcash was compromised from the start, as the company (Electric Coin Company) introduced a backdoor to help governments circumvent/bypass privacy features. I guess the only true privacy coin is Monero with its proven track record of development and innovation.
Governments don't like privacy, so they will do their best to bring the revolution down to the ground. It'll be up to us to help support privacy-preserving technologies to prevent governments from winning in the long run. As long as decentralization prevails, there should be nothing to worry about. Just my thoughts