what is profit?
profit is revenue minus expenses, where expenses are all expenses. sometimes some expenses are hidden, such as the owner of a business not including his wages in his calculation because, to him, all his profits and all his wages are the same (money in his pocket). some argue that in an efficient business, there would be no profit, because the price would be just above the cost, so the revenue would be just above expenses. however, if the transaction was agreed to voluntarily by each effected party, and each involved party was well informed, then each party benefited, or at least was not harmed, by the transaction occurring. if no-one would benefit, then there's no point in expending effort trying to make a change, so the effect must be net positive. if there's a positive, that means there was more benefit than cost, which means there is profit. where does the profit go? what's the fair way to distribute the profit? if only some parties get all the profit, then it's unfair, because they'll have a disproportionate increase in capital power. whether it's the employees, or the business owners, or the customers (as in the above example), or whoever else, is not important (though mitigation strategies may depend on who unfairly benefits). what i think makes sense is for some part of the profits being distributed among everyone equally as contributing to a sort of universal basic income (how much of the profits will go to this? this needs to be decided), and the rest to be distributed proportionate to how much each party contributed to the project (how is it decided how much one contributed to the project? this is a question that needs to be answered). the safety net is there without deterring the incentives, which are also there.
it's not the profit that is theft, it's the unfair distribution of profit that some people force on others which is akin to theft.
libertarians are against theft, because they are against violence (though some exclude violence which is 'necessary' to ensure restitution is completed), and theft (misappropriation) is a form of property violence. taxes are also a form of property violence, where the government uses coercion (credible threats) to scare you into paying, and if you don't, they 'make good', so to speak, on their threats by jailing you and forcibly appropriating (which is a form of misappropriation, hence theft) your the money they say you 'owe' them.
to say either is "unearned wages" is malapropos, as neither are wages (payment for labor).