Yes, No Deposit Bonuses have high wagering requirements because none will give you free money!
Yes we understand that there is no such thing as a free lunch however the ways that most of these binary options promote these "deposit bonuses" is with an invisible fine print pretty much. And this is probably another reason why many countries and credit card merchants forbid customers to trade with binary options.
I think if you put in BOLD and RED text asking if they confirm to "Wagering at least 20x rollover of the deposit bonuses AND no withdraws are possible without the 20x requirement and all funds will be forfeited" then it would be more fair.
However many people assume, they can deposit $1000, get $2000 total balance, lose $500, decide that binary options is not for them and try to withdraw the remaining $500 they have left and get declined. In my opinion the unlost money should be granted a refund at least. This is why many of these binary option sites have a bad history, its due to practises such as this.