I consider non-practicing Dionysians to be those who don’t, well, engage in the worship of Dionysos. Since there’s no set worship routine that’s a fairly subjective metric and I prefer not to concern myself overly much with what others do or don’t do. After all their relationship with Dionysos is necessarily going to differ from mine. They may only feel the need to pray and make offerings to him every couple of months and never have an element of ekstasis and enthousiasmos as part of their worship. Others still may feel that writing and talking about him is all the “worship” that’s necessary for them. I disagree, obviously, and feel that you get out of any relationship – divine or mortal – in direct proportion to what you put into it, so I’m always trying to find ways to deepen my connection with him and honor him. But ultimately I think such matters are best left between the individual and their deity. If Dionysos wants more from a person he’s quite capable of asking for it!
To answer the second part of your question – yeah, there are plenty of folks in the Hellenic and other polytheist communities whose opinions and actions I disagree with and who I feel do not, under any circumstances, speak for me. Even so I do not contest their right to claim such an identity for themselves. There’s no litmus test to belong to these religions, no office of the holy inquisition going around policing people’s thought and making sure that they conduct their rites in the proper manner – and we can thank the blessed Gods for that! While it’s annoying to see some megalomaniacal buffoon spouting off about “this is what True Hellenes do and believe” I don’t worry that outsiders are going to lump me in with them because it’s usually abundantly clear that we’ve got nothing in common. Most of them are ignorant of the primary sources our tradition is based on, just aping the arguments they’ve heard others make and too busy participating in endless online flame-wars to bother actually worshiping the Gods and celebrating their festivals. Quality shines through in the end, so I consider such people of no account and instead concern myself with my own practice. When I stand before Dionysos after my Journey West he’s not going to ask me, “Why didn’t you wag your finger at more people Sannion? You didn’t argue nearly enough.” He’s going to say, “You were fearless and creative, you danced and drank, sang my praises and lived every moment that was given you to the fullest – well done my son!” At least he’s going to say that if I’ve done my job well.