Original sentence: In the PRL era, football grounds and the supporters were one of the main opposition voices.Some fans are also far-right and/or ultra-nationalist activists.Usual displays and chants centre around nationalist themes, and stadiums can also serve as a recruiting grounds for the nationalist organizations
Edited sentence: Huge majority of the ultras are also far-right activists.Polish football firms (also known as a hooligan firms) are well known to be on the far-right, such as Śląsk Wrocław, Lech Poznań or Legia Warsaw.Stadiums serve also as a recruiting grounds for the nationalist organizations.Usual displays and chants during the games are patriotic and right-wing oriented