Honestly, I'm not sure what people are complaining about, it is supposed to be highest difficulty setting there is which is not hardcore mode. Of course it's supposed to be difficult that's the whole point?
If I had to guess I'd say people are insulted that they are having problems with the hardest difficulty setting, i.e. they would be much happier if tactician mode simply did not exist and classic mode was the most difficult setting.
Baldur's Gate had a hardcore mode too and it is substantially more brutal than tactician mode in D:OS 2.
