The problem is that a huge portion of humans are easily influenced and susceptible to propaganda.
If one party tells you that you have to adapt your lifestyle since using gas and oil for transportation and heating and eating meat every day is not going to work for longer and another party lies in your face that it's not a problem then people will totally fall for the bullshit that lets them live in ignorance.
Just look at how often you read the "100 companies" bullshit here that is shifting the blame but completely ignoring that personal responsibility has to come first so politicians have a chance. If a politician would suggest to triple prices on gas prices, flying and eating meat that politician would never win an election even though it would be necessary to do.
Sure the 100 billionaires that are emitting 1000x as much as a normal person are gigantic assholes and their emissions should be brought down but changing the emissions of a whole country has a far bigger effect.
If they're cracking down on the people gluing themselves to random objects/highways and, as is described in the article, assaulting others with rocks, then I see nothing wrong with that.
Seriously being treated as a terrorist and 30 days of jail for maybe glueing yourself on a street as polictical protest, is a normal fair reaction in your mind?
What's the alternative to be heard? Be quiet and hope that politicians will finally do something? We've been doing that for the past 40 years and it didn't work.
I'm gonna play the armchair psychologist for a moment and say it's probably related to the moral rebel effect. When people are confronted with someone saying that a group they're part of of is morally wrong, a lot of them tend to feel threatened and react aggressively. It's the reason why some many are instinctively aggressive towards vegans.
Basically, when some people see climate protesters reminding them that a lot of everyday choices they make are wrong, they perceive it as a personal attack and jump back to tribalism.
About the protest in France. At the time of the protest there was literally just a big hole in the ground, nothing that could be damaged by the protesters.
The protesters wanted to reach it, say that they are against it and leave.
But instead, for no valid reason since there is nothing to protect, the police attacked the protesters injuring hundred of protesters. They shot 5000 teargas grenades for 6000 protesters, including families that came for a peaceful protest.