I guess their activities fall under some weak definition of terrorism, intimidation against civilians in pursuit of political aims.
Nobody needs the right to say "I like ice cream" protected. Nobody would dare impinge on that in the first place. Protecting objectionable behavior is how rights are enshrined.
insert "there was no one left for me" poem etc.
Article 13 of the Universal Declaration of Human Rights:
* Everyone has the right to freedom of movement and residence within the borders of each state.
* Everyone has the right to leave any country, including his own, and to return to his country.
There are quibbles about stuff like precisely what year do we kill the oceans entirely or ho much will melting the artic will really do to raise sea levels. Along the way we appear to be so busy debating the specifics that that we have missed the point That as a planet we need oceans. We are animals who eat and breathe and we can't live if we decimate the biosphere in the name of burning fossil fuels in constantly increasing numbers.
IMO the real reason for this is to protect the automotive industry which is a large part of the German economy