They are quite serious. you may not agree with their tactics. none the less they are the ones putting themselves out there.

I do agree with you on some points. when I lived in Berlin their were people making gentrification difficult by placing small firelighters under the wheels of expensive cars on the streets.

Which would make no news, because it can be hidden away (as few people are affected by it), while landing the protestors in jail for ages due to destruction of private property.

In conclusion, unless it's a mass action by a significant percentage of the population, it would have little effect.

If I burn down an SUV, will this create less or more pollution than if it's driven and totalled after 80000km?

I've never heard of insurance for large scale projects which can lose tends of thousands to millions of dollars per operations day lost. That's normally eaten by the company's savings or loans. Maybe it's different in France.

If it's done enough, projects get delayed, profit is lost and insurance costs sky rocket.

Real politics is something you get invited to, not involved in.

No matter what climate activist do, they get shit on by people like you because big oil tells you what they do is bad. Stop being part of the problem.