Forza Horizon's demo was quite a bit more expansive than those examples.
Plus if you step outside of only racing game demos, then it's actually not that difficult to find demos that seem more on par with what DriveClub offers. Quake 3 Arena and Unreal Tournament both had demos offering multiple maps, all game modes, access to online, a good selection of characters etc. DriveClub's free version being more expansive than most demos isn't really enough to prevent it still being classified as a demo. There have been completely free demos of this scale before.
If this was just a freebie than I thing people would be looking at it differently, however it is in fact being offered as part of a service people are paying form, and likely in place of another game that would have been more complete. The closest comparison I can think of for DriveClub on current consoles is the new Killer Instinct, however you're not required to pay a sub to access this (or maintain access once you have it), and it actually provides free players with more of the games content overall, due to character rotations.
I don't really mind either way as I was always looking to purchase the full version as long as I liked the gameplay... but I don't think it's ridiculous for some people to be upset after having been told to expect "the exact same game, with maybe a few cars of tracks cut".