Brokers are playing those who are using brokers, those who are trading with any form of broker, and using it on their daily trade. They are being exploited through commission fees, trading fees, liquidation, and every other means necessary that the customer will enrich the broker owners.
You are getting almost all wrong, brokerage is a business and service, a middleman between traders and the market, do you expect them to offer their service for free? Of course, it has to be with tokens, and I don't see how these little tokens they charge translate to playing their clients.
Mind you, there are two types of retail brokers, one is an internal market maker, they earn when their clients lose and they lose when their clients win (paid winning from their pocket. This arrangement is fair, I see no one playing their clients here once they do not deny their withdrawal.
The other one is connected directly to the raw pool of the market, in which their clients win directly from the market and lose to the market. The former however could gain from the trader's loss, spread, commission and swap (which you didn't mention), while the latter will only gain from spread, commission and swap. This is a fiar arrangement since they are deploying their resources and technology to ensure you have access to the market which ordinarily can't be possible without them.
Also, the former can gain from liquidation of position, but the latter can't. Above all, all are dispensing their services with fair marked terms and conditions, it is the choice of anyone to deal with them.