That is precisely the answer. I'm surprised the writers of the article don't seem to get that. Read Alan Guth. Back in the 80s he and others postulated a slight asymmetry in the huge amount of stuff of the big bang: 50.00001% of it matter, 49.99999% of it antimatter. 99.99999% of all stuff annihilated and the remaining .00001% (which is all the galaxies in the known universe today) is the leftover matter from the slight imbalance.
If there were equal amounts of antimatter and matter today (as the article seems to yearn for), then there very soon there would be nothing.
Matter + antimatter -> annihilation -> nothing.
I guess they are saying we should be able to see whole galaxies of antimatter? Would we be able to see them and know that they are antimatter?
See the Xeelee series by Stephen Baxter, specifically “Transcendent.”
You will know those galaxies are antimatter when matter touches them ... keep a sharp eye out, the antimatter folks may be planning something big to revenge themselves.