But it's still abstract. It's still 'was prevented'/ 'has become'. “I think one of the reasons why discussion has become so unpleasant in this area is because for such a long time, that dialogue was prevented from happening.”
The implication can be misread as 'both sides'.
Not one side includes a gang of dangerous, violent, obsessive men who harm or threaten to harm everyone they come into contact with.
Janice Turner, also in The Times, is asking what it'll take for Bash Back to be classified as terrorists.