BeeLine founder here! I would guess that parent is referring to the fact that BeeLine assists with visual tracking during line transitions, and having a ragged edge (as opposed to justified) helps with this also. I've not seen people use right-justification as a way to achieve this, but the general consensus is that line transitions are easier when there's a ragged edge instead of justified text.
Oh hey! The funny thing is, I originally contacted BeeLine for a quote but was refused one without an already-existing website. So I resorted to experimenting with right-justification.