I see that you, and obviously others, think this is the way to bring attention to a situation that you are unhappy with. Speaking only for myself, I think it makes people against whatever the 'protest' is being staged for. If I start out agreeing with you, but this type of situation arises, and messes up my life or my property or whatever, it tends to change my mind. Then instead of looking for justice for the victim, like Mr Gray, you start wanting to punish the protesters, whether peaceful or not.
Otherwise, don't punish me for what someone else did, or I may try to punish you for what people who think they are supporting you did. (I don't know if that makes sense.) I just feel we all lose sight of the root issue, cause now we have to deal with all the collateral damage.
This is all MOO.