> initially a reasonable oppositiin movement, it became full of antivax and destroyers if common property
What's your source?
About direct action and sabotage, of course some of the movement engages in such tactics, as most protest/revolutionary movements have over the years, because that's the only way to get the message across when nobody in power wants to listen to your reasonable requests. That's the only way i know of the make the nationwide media talk of social issues and popular protests... If you have other ideas, i'm sure plenty of people are interested.
Specifically about direct action, as the name implies, the action itself is the objective. Burning trashcans and blocking streets sends a message, but attacking the institutions (eg. banks) directly responsible for our suffering, whether we agree with it or not, is a relevant political strategy that has been part of revolutionary and anti-colonial struggles since as long as history has been written, and arguably longer. Do you think the resistance movement from the 40s blowing up trains and assassinations of nazi officers was illegitimate? Or do you think the situation is possible, and the endless destruction of our planet along with deteriorating social conditions for the global populations does not warrant being angry and attacking those directly profiting from this situation?
About anti-vaxxers in the gilets jaunes movement, from what i could see it was pretty divided. Moreover, i would argue the government's lies and coverups all along the pandemic has greatly helped anti-vaxxing conspiracy theories. People don't trust the government, because the government doesn't have our interests at heart. Moreover, there is a growing distrust of the scientific community, which i personally credit to key institutions from academia and media giving scientific credit to many discredited ideas: downplaying the seriousness of climate change, advertising for urbanization as "progress" despite medical evidence pointing to inherent problems in the modern way of life, or pushing for the "green revolution" since the 50s despite solid scientific evidence that mechanized monoculture is damaging the environment and not sustainable yield-wise (we are already witnessing in Europe the first signs of desertification such as land dry, due to such techniques).
Of course, most vaccines are good. But to be honest, most people i met who you would probably label "anti-vaxxers" are not anti-vaccines, but rather skeptical of the results and side-effects, which is a good critical posture. Many people who were skeptical at first are now getting vaccinated and that's a good thing. Of course, the government trying to actually force people to get vaccinated is not helping the situation. Instead, making the vaccine widely available for free, even for those who don't have social security, would help it reach more people, and would probably help convince those who are still skeptical.
After all, the government never has our best interests at heart. In this specific case of Covid vaccines, its actions are not against our best interests (no hidden chip or autism serum in there), but for the financial interests of the pharmaceutical industry it's subsidizing through this scheme. Once again, if the government forced nobody but made the vaccine widely-available, requisitioning the pharmaceutical industry to produce it at cost, more people would be inclined to get vaccinated.
> up until the moment they get power and realze that their claims do not hold water.
So this is a divisive issue in the gilets jaunes movement since of course not everybody is an anarchist. However, a lot of people in the movement want to destroy power, not seize it. There is a strong anti-party sentiment across the gilets jaunes movement: elections are rightfully seen as the opposite of democracy (giving power away from the people), and many components of the movements advocate explicitly for decentralization of power through local assemblies, even holding "Commune of the Communes" (or assembly of assemblies) conferences to federate those smaller initiatives without centralized power.
As a conclusion, i'm not saying i feel sympathy for the entirety of the movement as we have our disagreements. For example, i don't have any sympathy for royalists and neo-fascists infiltrating the movement, and i'm glad they were kicked out of demos by the protesters themselves in some cities. However, your talking points appear to be regurgitated from government propaganda. Are you actually talking with people who identify with the gilets jaunes movement?