I saw the backwards statement... it felt like a speed bump with a sign right after it that said, "carry on" (since the second part of the sentence clearly showed they knew what they were saying).
But again... unless you are designing semiconductors, it's OK to just use the conventional flow concept because it's not critical to know which way... just that it "does" or "does not" ( and accept that MOSFET people are anti-social -- I mean non-conventional).