Why do some people did not like the Resident Evil 6?

People who really hate/dislike the last titles of the franchise are from the old school, when RE gave a lot of tension to the player, trying to find a save room, or when the music changes and you knew something was going to happen. Those feels were cut when RE5 came out (personally RE4 was cool). I include myself when talking 'bout this, I really hate the last titles, Crapcom just said: ok, we're a bit tired of this old school sht, let's put some explosions, remove the zombies, put some "infected" with guns and expands the story way beyond the cosmos and knowledge. And now they're like: eat our sht and give us money. Just an opinion from a veteran on RE saga

Because taste varies between people.

When a series evolves (or devolves), it often loses things that made the previous titles good. Some titles manage to lose a lot of good points but gain nothing in exchange. Sometimes the change of flavour/feel can alienate fans of the other games.

For instance, I enjoyed the early Resident Evil titles when I was younger, but if I tried to play them now, I'd probably hate them. I really liked RE4 and found RE5 to be fairly good. I absolutely hated revelations at first, but it grew on me once I let go of the lack of reactions to being hit (and the horrible dodge mechanic).

I think RE6 lost a lot of points for being clumsy in the handling of it's instant-death chapter moments, and ended up causing a lot of restarts without ever properly highlighting your options for contextual actions, or giving the impression that you weren't supposed to kill something by pouring a ton of bullets into it (and visa-versa). I actually enjoyed RE6 but specific chapters/characters were very frustrating in comparison to others. Leon's route being my favourite, Chris being fairly good, and the other two simmering in a whole lot of shruggable frustration. Compared to RE4 and RE5, it was a weaker title.

A bad game makes people regret purchasing it, but they will just rant and get over it after a little while.
It's worse when you see a lot of wasted potential, perhaps.

Who ever played resident evil 1, 2 and 3 should never player crapident evil 4,5,6,7,8,9, etc...

Because I was scared to buy it after the nauseating clusterfuck that was Resident Evil 5 on PC.

Not everyone likes a good game for himself.

I hate RE6 as a resi game, it was ok in itself, Only good for co-op, i regret buying it near release date

Because everyone is entitled to their own opinions?