Cryptopia gets bashed whenever a coin has issues. People tend to talk shit until the problem is solved. The Cryptopia team have to solve a lot of problems that the coin developers should be solving - that is why some coins get delisted after the initial problem is solved.
Cryptopia has only recently grown to a big exchange. To some of us it is more like a big family. Longterm members like myself are protective of this exchange.
EDIT: I notice that Cryptopia also now have issued an official response:
https://www.cryptopia.co.nz/NewsThis official response and your arguments are 100% fiction. Before the delisting Cryptopia wrote about some "enterprise level" wallet bullshit. Signatum devs are always in the discord and communicating with community almost every day. If cryptopia wrote here something like "sigt should update their leveldb version to 1.XX", than community immediately asked devs "WTF?" But they pointed this after delisting. That's why i think all those argumentation is bullshit like these "enterprise level" arguments.
P.S.
Pointing to the delisting reason after delisting really unprofessional and stupid.