I had a bottom of the range (and I mean absolute poverty spec) 1.2 P reg Corsa for about 4 years in that time I took it from less than 40K to well in excess of 100k so I think I'm reasonably qualified to say that it wasn't a bad little car.
So what? I used a Nokia 6110 for a year and I think I'm qualified to say it wasn't a bad phone. But would you buy one or recommend one? of course not as it's easily eclipsed by a number of significantly better options these days! Just because something is average doesn't make it ok if there are numerous BETTER ALTERNATIVES for the SAME MONEY.
This is the point the former Corsa owners seem to miss. Yes you had a Corsa, great it got you from A to B. But you saved zero money over chosing something else, and something else would have been better. Therefore the Corsa was, fit for purpose or not, a bad choice.
It's this sort of attitude that keep sub standard products on our shelves. Would buy Tesco Cola if Coke was the same price? Of course not even though Tesco cola would quench your thirst.