High profile protests like this keep the matter of climate change in the spotlight. They prevent it being brushed under the rug by other events and ensure it remains on the political radar. Maybe you’re right in that if you don’t care about climate change JSO are unlikely to change your mind, but if they help to convert even a handful of people, or at least encourage conversations on the topic that they weren’t having before, that’s a win.
The majority of people see climate action as a priority:
https://www.cleanenergywire.org/factsheets/global-surveys-show-peoples-growing-concern-about-climate-change
https://www.pewresearch.org/global/2021/09/14/in-response-to-climate-change-citizens-in-advanced-economies-are-willing-to-alter-how-they-live-and-work/#:~:text=A median of 80%25 across,or no changes at all
https://nielseniq.com/global/en/insights/report/2023/consumers-care-about-sustainability-and-back-it-up-with-their-wallets/
The reason not everyone is voting accordingly is because political motivation is complex. There’s more things pressing for people’s attention like being able to feed, cloth and home themselves. That’s why addressing societal issues like poverty, inequality etc are part of addressing climate change. We need to free up people’s bandwidth to allow them to concentrate on issues like the climate.