A lot of sellers give false information about their products, and they get really angry when you complain about it.
Just look for "philips 50000mAh" power banks, for instance.
They often defy physics by having more storage capability per weight than is theoretically possible for LiPo batteries.
LED lights and similar often exaggerate their light output by at least a factor 2, sometimes 10.
That said, I'm happy with quite a lot of aliexpress products, so I think that aliexpress would be great if they started to clear out the false information.