If the concept of "good" is different for each individual, surely the concept of "right" is as well.

To the extent that there is a difference, yes, this is true. Eating sweets may be "right" for you or me, but not for someone who has diabetes. Learning computer programming may be "right" for you or me, but not for someone whose talents and interests make them much better suited to be a plumber.

But as I said, there is a lot of overlap, and where there is overlap, people share a concept of "right". There is pretty general agreement that it's "right" not to murder people, for example.

Do you have anything to back up this claim? It seems very wishy-washy.

It seems obvious to me. Nobody else shares your experience; nobody else lives life from your point of view.

There are all sorts of power, and all sorts of ways one can hold another in power.

True, but not all of them involve influence or advice. I don't ask my local cop for advice. I certainly don't ask my Congressman for advice, although lots of people do look to their Congressman for guidance on political issues (more on that below). The cop and the Congressman are basically my agents; I've contracted them (through a very convoluted process, true) to take care of certain things that we, as a society, have generally agreed need to be taken care of. That relationship does involve giving the cop and the Congressman certain powers, yes; and not all of them are good ideas, IMO. But it's not the kind of power you're talking about (or it shouldn't be--again, more on that below).

you seem to be arguing that someone is wrong for considering a person worthy of giving advice, and putting that person in a "position of power" by allowing them to speak that advice.

It depends on what you mean by "advice". There's advice, as in "tell me what you think" vs. advice as in "tell me what I should do". The former seems fine to me; you're just seeking information. The latter does not; you're asking someone else to make a decision that you should be making yourself.

There is an important special case, though, which I alluded to above. What about appointing a specialist, so to speak, as your agent in an area where they have special expertise? That's what the cop is, basically; and the same goes for doctors, lawyers, and other experts that we hire. The same is supposed to go for the Congressman too; they are supposed to be specialists in politics, in coming up with consensus solutions to difficult issues.

That was supposed to be how the US government worked: it was supposed to be a republic, where people elected representatives who were supposed to have better than average knowledge and judgment about politics. That means the representatives are not really giving advice or guidance; they're not telling you how to vote. They're just doing the job they were hired to do; and if you don't like the job they're doing, you vote them out.

But now every political issue has to be decided by popular consensus--not just consensus of the representatives, but consensus of all the people. And so now people look to their politicians to tell them what to think, instead of exercising their own independent judgment about how well their politicians are doing their jobs. In other words, the fact that people expect politicians to give "advice" and guidance is a sign that the system is broken.