Perhaps I'm remembering things incorrectly, but I think the voting was deemed illegal by a court. In that sense, the police using force to stop it is OK. Whether doing so was a good idea or in the spirit of democracy might be an issue, but strictly speaking (and assuming correct court judgement), everything seems to have went according to the law.
I don't think the situation was handled in an acceptable manner, but there don't seem to be any really serious issues.