Martingale has negative expectation so it's the users who are susceptible to it, not the site.
(Casinos avoid it because its procedurally disruptive, and rapidly ruins customers they're rather milk, not because it makes the games net positive for the players)
satoshidice has a very wide dynamic range... doing the standard 2x martingale, it allows up to 17 losses in a row... you won't get anywhere near that at a regular casino... more like 4 or 5 in a row.
the key to reducing martingale risk (for the house) is bringing the min/max closer together.