Why should every political statement, or rally, have to have a permit?
That was my anarchist hat, or if you prefer, my anti-big government one.
Because, as in this case, you just look like a vandal.
Personally I would have taken it as a racist statement and would have taken it down in the same way I would pick up litter that someone tossed.
If you want to have your rally get a permit so I know to go somewhere else. Because if I find my car suddenly surrounded by people chanting and waving signs I am going to presume they are not friendly. And if there is no exit I will make one.
The black-tape "speechers" seized, and tagged, a public space, in effect forced the tuition-payers and (presumably) taxpayers to pay to provide a forum for their expression in a public space. But vandalizing public property by taping terroristic jingles on the sidewalk, does not constitute a simple political statement.
And it was the people who "rallied" to preserved the openness and neutrality of the public space, and removed the sinister vandalism, who exercised their right to rally.
Symbolic speech meets more symbolic speech.
My tentative argument.