I think the key difference here though. Is that XR are not protesting they are disrupting. Even if you changed legislation it wouldn't prevent them, they deliberately disrupt and antagonise in an attempt to get arrested that IS their goal. I would like to think it's some kind of roundabout thinking that "if you think WE are disruptive wait until actual climate change happens" but also their key is merely to highlight the issue and therefore by being as disruptive as possible it increases the chances of their "protest" being newsworthy, or at least, newsworthy for the longest period of time. Perhaps you could lock them up quicker with new legislation but as you elaborate in the post, it then begins to infringe on genuine protest that doesn't intend to solely disrupt but to actually protest a perceived injustice or societal issue.