"I've heard of egalitarianism. Is equalist a dumbed down form of the same thing or an MRA type movement?"
Equalist is just a more modern, easier to say term than egalitarianism - it is not dumbed down, they mean the same thing and are often used interchangeably.
"Do I sense an assumption that feminists (or anti-racist activists or LGBT rights activists or disability rights activists etc) only give a shit about one type of oppression?"
Only because you choose to read something that isn't there. Feminists often self define their beliefs as seeing things from the female perspective - it was done on the first thread wrt education when a feminist poster said they will look at things from a female perspective and leave arguements around boys eductaion to mens rights activists. Dittany said it earlier on this morning in relation to improving rights for mothers in the workplace ("Do we really need to be nice to people with a father's rights agenda..").
As an equalist, I would argue that from my perspective that is too narrow. I care about eductation for children, I will not narrow my perspective to focus only on my gender. I also believe that if you want to fully achieve equality for mothers in the workplace, then yes, you do need to work in partnership with the fathers rights agendas because the only way that you will ever achieve true equality for women is if men a not treated as inferior for wanting to stay at home and raise their kids while their wife works.
Some feminists such as Trillian said they saw their idea of feminism as encompassing equal rights for both genders, which is great. But for me, and many other equalists, too many feminists do choose to focus purely on female gender issues for me to be comfortable calling myself a feminist.
There are also differing viewpoints around whether equality should be about tackling the situation today or righting past wrongs (the old "men have had it easy for too long arguement, who cares if they lose out a bit now") and over issues such as affirmitive action / positive discrimination.
"You talk about equalism as if it's an established political ideology/movement. Is it?"
Mostly it is a philosophy, but it is starting to gain ground as a political movement - it is still in it's infancy.
However, I am not sure of the value of a full blown political movement given the amount of crossover with established political movements (feminism, gay rights, race relations etc) which it would be more productive to work with rather than set up alongside and split issues on which we basically agree. Perhaps we need a mini movement to deal with the issues and points where we differ.