They don't have to give extra extra rewards if they know they are doing their business right.
It's just a marketing ploy to attract new users, what's wrong with that?
As you said, it is a marketing ploy, they are deceiving users by wrong marketing propaganda. However, I have seen that most of the noobs here have negative trust because of supporting this exchange. I hope the exchange will make it right as soon as possible and please -- the exchange should not claim to be the no. 1 cryptoexchange launched in 2018. We all know very well that claim is not true. Please don't mislead newbie traders to this false claim.