These low-rated reviews are being way too serious about a movie that is a comedy, and not to be considered too seriously.
That being said, the movie is actually funny, and even it's not hilarious to some, it'll make you smile at least. People only think this is a stupid movie because it's filmed and not animated, but the amount of stupid moments that come out of Family Guy and American Dad is ridiculous, but we still laugh! Why? Because watching a real-life version seems badly written, inappropriate and immature.
This is light, compared watch Family Guy spew out to the many mindless viewers out there. I just wish people would understand that comedy is meant to be something that shouldn't be taken too seriously, otherwise we'd all be watching lighter, less offensive comedy, and where's the fun in that?