You made a good point about that old schoolmaster style "this is how it should be done!". It might look neat but is it the safest and most appropriate way now?
I have been boll**ed before by a civvy FI when I took off on the right parallel runway and turned 5* to the right to give a little bit more separation (at maybe 100') from the left runway. It was a very gentle bank BTW less than 5*.
"no turn below 500'!" I was told. Why? Apart from the fact I am used to doing full turnbacks from 300' I specifically did this because there was a fatal collision from just this sort of departure where the left guy drifted to the right, and the right guy drifted to the left. And seeing the attempts some students make........, that bit to the right might save your bacon.
I was just being a bit proactive and roasted for not following proceedure to the letter. This kind of attitude just doesn't make sense to me.