Well they did make black holes to look for the this higss Boson. As all black holes we know suck material to them like a big hover, it is not unrealistic to think this could happen.
The thing is that we do not know how big the critical mass is for a big hole to start growing. Off-course the scientists stated the critical mass was not big enough (and others stated it was) and the lifetime of the black holes was to short for them to grow. But scientists have been wrong before ...
The good old "better safe than sorry" is not the credo for the people working with the LHC
We now do know that the black holes they produced did not reach the critical mass.
Greetings from Belgium
Jantje