For some, BJJ is a way of life. But in terms of goals and how it is applied, things can vary greatly. As my coach says, BJJ is necessary for MMA but not the other way around. And personally I am fine with that. Some enjoy BJJ as a pure art, just for the competition. Others, use it as a tool to help them fight in the cage.
If you never claim that it is more or less than what it truly is (i.e. being honest) then I feel that nobody can really say anything bad regarding that.
However, if you solely train BJJ but act like you are an accomplished MMA fighter... then you are just deluding yourself. This applies really to anything else really... such as Taekwondo, Kung Fu, Judo, wrestling, etc.
The "base" argument from where this stemmed from was years ago when relatively unskilled people fought each other just using ONE style. When that happened, then yes the BJJ guys most certainly dominated.
But again, nowadays people know better and mix up the styles.
Now a slick submission by Jordan Schultz