That is indeed a valid observation, could this mean these people don't actually have any BCH, which would imply that they are fake supporters of BCH? Good thinking!
Not really. I, for example, don't feel like answering to Grumpy on reddit, and then here.
Looking at myself, I don't stop myself to promote my ideas and thinking one platform while not doing the same on another. Redit, Twitter are free, Memo is not so that's a good clue.