I someone says "You're using too much arm", it sounds like a form problem or MMC or both. Hard for anyone here to really know without a vid.
When I start my back exercises my first w/u sets are slowish and deliberate so that I actually feel my lats contract and hold to initiate that MMC. I never thought of it the way stu describes it but that's exactly what I do (and great way to describe it).
And from an actual "rowing" (like a shell on the water) perspective that's how you're trained: leg drive, hip-lowerback-upperback/shoulders, arms, release. You're arms/hands are just hooks to attach to the weight, they shouldn't be doing 'the work' on a 'back exercise'.
As far as biceps before back asking for injury, I don't know. I do my biceps before back on one of my two back days. I find that I end up taking biceps out of the movement more and I don't turn my back exercises into biceps exercises.