Not true but compared to the rest we are unique. I mean we are human. The Asari have power, The Turians have the largest fleet, bigger than the Asari and salarians combined, and salarians are geniuses when it comes to technology.
If by unique you mean better, then yes.
The Asari hordes technology from the Protheans, whereas humanity makes their own advances and therefore isn't reliant on it for their power like they are. The Turians have the largest fleet, but humanity is better equipped and tactfully minded than them; lets not forget that apparently everyone else in the milky way was too stupid to come up with the concept of a carrier class ship except humanity. The Salarians are the mad scientists of the galaxy, and yet humanity is the one to come up with a universal medical treatment in the form of medi gel. The Volus created and manage the galactic economy, but humanity is soundly dominating the market. Etc.
By the end of the trilogy humanity was at the forefront of everything, and every other known species in the galaxy recognized our superiority and deferred to our judgment. Heck the whole driving force behind ME 3 was to convince all the other species to drop what they were doing and help us "Take Back Earth"; the Crucible was an afterthought most of the time, and the allied forces were planning on pushing to liberate the human homeworld long before the Reapers moved the Citadel into orbit thereby giving an actual plot reason to go there.
So yes (IMO), having a "Humanity first!" group is redundant in this universe.