Who told you they were all fake?
Alot of them especially the diamonds are very real. Extremely high quality items as usual.
These are mostly liquidated overstocks or the rest consist of quality designer inspired goods, some of it authorized.
Some also have very good relationships with the distributors. They have a feedback rating of well over 65 and are hard to spot however, as the rest of the sellers there do in fact sell full fakes.
The Diamonds are 100% real for SOME of the merchandise as well as the silver. But its one huge listing house, and unless you know exactly what you are doing you would stay away from DHGate.
There are a very rare few who get good wholesale merchandise, and when they do they will actually tell you and be more honest.
The run of the mill sellers or majority are just there to peddle fake gemstones, million dollar piles of sand and so on. DHGate recommends everyone stay away from them. The small quantity of very good suppliers there have 100% high feedback for their diamonds and, you will have a tough time always unless you can keep them as repeat vendors before they move to another station.