Only if you take the profit from their labor without their consent, as in taxation.People who argue that "involuntary socialism" is theft, well you could certainly argue that using someone's labor while taking the profit is the same exact "theft."
So if capitalism = competition, then socialism = sharing.
What does capitalism have to do with any of this? Capitalism = voluntarism. In a capitalist economy, nobody takes the profit from the product of anyone's labor without his consent. Labor for others is only done pursuant to a contract that is entered into voluntarily by all parties. In other words, you can opt out of the job offered to you by the capitalist. You cannot opt out of the gun pointed at you by the socialist.