Do dealing desk brokers have to lose if you win?

Do dealing desk brokers have to lose if you win? Meaning, do they have the option to act as an ECN for certain traders if those traders are actually profitable? Or, if a trader is profitable, that means a dealing desk broker has to be losing money because of them, if what the trader makes is more than the spreads / commissions the broker makes from their trades? Because if it's the case that a dealing desk has to lose if you win, then how could anyone ever feel comfortable using one? And, why is it even legal for brokers to act as dealing desks? It's such a blatant conflict of interest.

A dealing desk will offset all the longs against all the shorts using an algo, anyrthing left over is hedged to his luiquidity providers. He is free to tray to "pick a loser" but thats just a side bet he can make. He cant "make" you lose, but he can bet against the 99% if he so chose and Im sure they "choose"

In other words NOT hedge your trade and just keep your loss.

be broker more profitable than be trader , traders will going to lose money even if broker respectable so better he take this money traders left on table :")