Back in the bad old days, you'd buy a 3 pound can of Blue Ribbon hopped malt syrup and mix that with a can of sugar to make 5 gallons of beer. So the fermentables were over 50% cane sugar. It did indeed get a nasty "cidery" taste. Maybe all it needed was some yeast nutrient.
When I started homebrewing 20 years ago (lost interest after a few years, then picked it up again a year ago) The New Complete Joy of Homebrewing was about the only reference book, and it warned (way too much) about not using sugar. I wish I knew then how well granulated sugar works for priming.