> The main reason to have taxes is to fund the government, not to make society a more just society.

Both are important reasons for taxes.

"We can have democracy in this country, or we can have great wealth concentrated in the hands of a few, but we cannot have both." (often attributed to Louis Brandeis, though he probably never said exactly the quote)

Taxation is one of the primary tools for avoiding destructive levels of wealth concentration.

Of course, the wealthy decry this as unfair wealth redistribution but all governments engage in constant wealth redistribution.

In the US we happen to have decided (since the Reagan era) that through increasingly regressive taxes the redistribution will almost always function upwards, ultimately resulting in the oligarchical dismantling of our government that we find ourselves in today.