Here's my take on it.

Income tax is more like slavery than theft. It's essentially the government coming and saying "You will no longer write code 100% of the time. You will only do so 65% of the time. For the balance, we'd like you to dig ditches."

I would argue that taxes on real assets (i.e. land) are morally justified. The moral justification for private land ownership is largely based on John Locke's Second Treatise of Government where he lays out the conditions for how a resource in its natural state becomes privately owned. The caveat is that the right to appropriate land cannot be exclusive of anyone else's right to do so. Meaning you can't put all of the land on earth to productive use and claim ownership of it. On the other hand you don't want some rando coming to your land and saying "I have nowhere to build my home so I am taking a piece of yours," even though on a moral level if all land is privately owned he would have the right to do so. We do want property in the hands of those who will make the most productive use, so I'd suggest that a tax on said property would be a moral way of ensuring fairness in a society.