People can be perfectly justified in saying they think a game is 'bad', regardless of how well-reviewed it might be--that's the nature of opinion and critique. For instance, GTA V has 97% on Metacritic, but I think it's a genuinely awful game - easily the worst Rockstar's ever made - and if I could be bothered to write a few thousand words on the topic, I could explain exactly why. I'm not wrong to think that, just as the people who wrote the reviews that gave it that 97% score weren't wrong to praise it.
Critics aren't expected to append 'imo' to everything they write, and nor should they be.