I think there are a number of problems with this form of violent protest. First, I don't see how this vandalism accomplishes anything positive. It doesn't help anyone. It doesn't punish BP. It doesn't conserve a single drop of oil. It doesn't draw attention to an unknown problem (anyone who doesn't know about the Gulf oil spill is living in a cave). At best, this energy is wasted and should have been used on more productive endeavors. Second, the violence is against a relatively innocent third party. The Gallery in no way causes BPs actions. They neither buy nor sell from them. Virtually nothing in the universe would be different if they had refused BPs donations. They are 'guilty' of accepting a gift. I seriously doubt there is anyone who thinks, 'well, the oil spill is terrible, but BP is a fine organization because they donate to Tate.' It is hard for me to see why 'accepting legal donations from an environmentally reckless company' would merit this style of violence. Third, this sort of ...

I would say that there are at least two competing values in contemporary liberalism: liberty and equality. Minimum wage laws serve to increase economic equality by eliminating the possibility that someone might get paid less than the 'minimum wage'. Yet you are quite right that minimum wage laws are illiberal in that they eliminate one's liberty to hire and work at a lower wage. On the whole, it seems like a worthwhile trade off to me. I'd also point out that this kind of liberty is less meaningful to someone who is so poor that they would be inclined to accept ultra-low wages out of economic desperation.... some of us would regard such a contract as 'exploitation'.

You appear to be asking the question: "how can someone make decent money, without taking part in the only established system for making money"... the obvious answer is that they can't. If someone judges the economic system to be unjust, their options are rather limited. They can try to move to a place with a more just system of economics (good luck, there are probably a few places that are more 'fair' but most places are worse IMO). They can try to withdraw from the system in some way, perhaps by living off the land in a commune of some kind or by taking a vow of poverty and joining a religious order. Probably, the most practical of the options is to begrudgingly take part in the system while working to reform it from inside (again good luck, reforms happen slowly and unintended consequences are common). But in any case, if you find contemporary capitalism to be fundamentally unjust I'd suggest that 'making decent money' should no longer be an overriding goal for you. After all, isn't the current system...

It seems likely to me that there are some situations where such arguments are based on a fallacious 'inappropriate appeal to authority,' but that there are other circumstances where the views of the founders are deeply relevant. For example, if the question is 'how should the first amendment be interpreted' the actual views of the people who wrote the first amendment seem extremely relevant. Naturally, even in this situation we can criticize the founders and argue that we should believe something different than they did. Of course, there are other times when such arguments seem quite irrelevant. For example, George Washington warned against maintaining a 'standing army' but the realities of the 21st century seem to make his view quite impractical. What bothers me more about these types of arguments is that people who make them (IMO) are often incorrect about what the Founders believed or at least engage in very selective 'memory' concerning them.

According to political philosophers like John Locke, we all receive certain benefits from government that make us better off than we would be in the 'state of nature.' As long as government makes us 'better off' on the whole over the 'state of nature' Locke says that it is a just situation. So, taking a certain amount of money through taxation is a small harm compared to the benefits of living in a stable and civilized society. In contrast, if we were enslaved by a government that 'forced us to work,' we would be worse off than in the 'state of nature.' In the state of nature Locke believes we have our life, liberty, and property.... any government that significantly infringes on these rights is unjust. I should point out that Locke seemed to think that even the limited taxation of his day was a 'necessary evil.' It is unlikely that he would have approved of our current degree of taxation.... of course, we also get benefits that Locke never would have imagined.