[getrealal]

They are far-left activists who went to fight alongside Kurdish militias of the YPG, a group affiliated with the PKK, considered a terrorist organisation by the European Union.

That is why they were put under surveillance when they came back to France.

Here is a reference in French: https://fr.wikipedia.org/wiki/Affaire_du_8_d%C3%A9cembre_202...

Ultimately it's a bit more complicated than good people fighting versus evil people (and as far as I'm concerned, they were effectively fighting for a US proxy against another US proxy).