Not necessarily an outright fallacy. More like a case of a potentially false assumption, and in 'usually X means Y' arguments, that sort of argument easily lends itself to more subjective rather than objective perspectives.
It's not necessarily a bad thing, although like most methods of making a point, it can be used for bad things.
Generally if someone uses this sort of wording, try to apply a principle of charity to what they're saying and interpret whatever it is in the most positive manner it can be interpreted, and then ask if that's what they mean.
Edit: It should be noted that with 'usually x means y,' it's very easily possible to fall into making some fallacies, depending on how you justify 'usually x means y.'