BS”D
The problem is that ‘we all look the same’ and these demonstrations get out of hand.
Remember that the ShaBaK and police have infiltrated the ranks of the shababnikim and that therefore the crowd is full of those who want to create a chilul Hashem, whether out of misplaced kanoius or, more often, davka to make us look bad.
The only way for these demonstrations to work without chilul Hashem is for a calm group to create a kiddush Hashem by demonstrating in one tightly packed spot, making sure that all who are there agree to learn, say Tehillim, sing together, or otherwise make it clear that they are not part of any violence.