what they are doing seems like honest trading to me. Buy when the price is low, then sell when its high. I guess many people try to use tether, the biggest currency that does not follow overall cypto trends, as a hedge and for day trading.
Issuing unbacked tether is what people expected anyways. When you buy tether you know the risks. Actually find it rather surprising that there only seems to be temporary fractional reserve lending and they actually sell back btc to back it.
I wonder why tether is so successful btw. isn't bitUSD the obvious superior choice?