Forex Brokers List

Dukascopy is a market maker. But because they're one of the largest market makers, they have a unique ability to create their own ECN-like trading environment in-house. This means they have enough liquidity (enough trading participants) to facilitate any amount of trading and any style without the need of external liquidity (most of the time).
Dukascopy is one of the very few Forex brokers who is large enough to afford such ECN-like trading environment. 99% of other brokers can't. That's why they might answer this way in order to differentiate themselves from other brokers, and without going into much details about ECN-specific rules.