Stewart,
I’ll call your saying only once thingy and raise you one.
If I am using a file with more pressure than any human can and achieve excellent results and get a really well performing saw, then there can be no issues with the file for hand filing users. I use a machine because it yields better results than anyone could by hand. Perfect exact angles every time. Fleam and Rake, all the same.
Really sorry you got got a bad batch of files 5 years ago. Perhaps it’s time to get over it and move on. It is, as they say, a bit of an old chestnut.