I remember the use of chalk, mostly from college. While I never really agreed with the messages that were written along the path back and forth to class, I only remember the message of one of support of a cause and never a personal attack on anyone. They were annoying, but it was to a general audience and not permanent to property.
This past week two Chick-fil-a's were tagged with hate, a permanent marker, that required cleanup. The defense for one artist was that it was a protest, he still needs to pay for the clean up. If anything he will be more admired in is small niche, who may think what he did was courageous.
Graffiti is bad no matter what, but if it was in an urban area we take graffiti as if it was litter, it destroys the whole community. It hurts everyone. It demoralizes us. It says our community as a whole is not to be respected and to be defaced.
Freedom of speech is important, and when people take advantage of our freedoms to peacefully and without malice to protest a disagreement with publicity stunts such as tagging property, it takes away everyone's right to speak. Restrictions will be placed to stop graffiti (temporary or permanent), but it may push back an individuals ability to even be adjacent to private property when in protest. In Massachusetts we have 30 foot protest boundaries around abortion clinics to protect them from protests. Should we have 30 foot boundaries for every business?
Chalking on public sidewalks, I'm sure has it protections. Now though, how personalize and sad it has turned.