Typically proponents of "social justice" (in the sense of the political term) tend to be on more on the left.
"Social justice" as a philosophical concept sounds great, but the ways that the left or the right (or anyone in between) wants to implement (or specifically not implement) policies is what changes the game a little bit. In the United States, this term is associated with liberal politics (I can't speak for other countries).
Not sure if you've heard of the term social justice warrior (oops, I just referenced Urban Dictionary), but usually those who lean right use it as a pejorative term for enthusiastic proponents of "social justice" (I just use this as an example to point out that the term "social justice" is specifically used as the root of this pejorative term because it targets those on the left). Stephen Crowder is a popular conservative comedian and speaker who uses this term frequently when discussing liberal politics, if you want to see how "SJW" is used in common discourse.
I think in this case, it's less about the actual philosophical meaning of the phrase, and more about how it's used on a day-to-day basis. You might hear a conservative use the term "social justice", and if they do, they'll either be:
- talking about a completely different implementation of it than liberals
- or they'll be using it when discussing liberal politics.
Edit (based on edited question)
tend towards respect for the individual or for the collective?
That's an interesting question, and I think the answer is that they tend to respect a specific collective to which they belong or would like to belong (in other words, they respect the individual rights of only members of a certain group). That is, they don't want poor people to be poor, and they don't want rich people to be rich. I'll link to one of Crowder's videos (take it all with a grain of salt, and keep in mind he's a huge conservative proponent, and his videos are meant to be comedic), but he says something interesting which echoes this point. He says this when mimicking a certain liberal presidential candidate who is a social justice proponent:
The 1% will try to convince you that I don't like freedom. I like freedom, as long as it's not for people who are too rich or are too poor. I want freedom for everyone of the people in the middle, and it needs to be government mandated.
This hits on a couple of interesting points (specifically the difference in how conservatives and liberals might define the implementation of "social justice": whether it should or shouldn't be government mandated). According to this philosophy, it is unjust for rich people to be rich because they are withholding things from other people, and it is unjust for poor people to be poor because they don't have things they deserve. The solution to this, then, is to take from the ones who aren't giving, and give it to the ones who need it.
Following this, you would end up with a group of people in the middle, and this is the "specific collective" I mentioned that proponents for social justice seem to strive for: equality of outcome versus equality of opportunity.
an increased belief in the rights and privileges of the self combined with a very high regard for and propensity towards making claims of altruism
"The rights and privileges of self" are rights and privileges that they believe should be given to them from somebody else, and the "claims of altruism" often involve taking from those who aren't worthy to have the same rights and privileges ("the 1%" in this case are the ones who aren't worthy) and giving to those who they believe are worthy of certain rights and privileges. In other words, "the rights and privileges of self" only take into account the rights and privileges of those who belong to a specific group. This isn't social justice for everybody; this is social justice for a specific collective.