Mostly Hungarian Hungarians, but yes, it's in Transylvania, Romania, originally this event was a dual, Romanian-Hungarian cultural and political festival, but Orbán took it over in 2010, you can read the history of the festival in Wikipedia: https://en.wikipedia.org/wiki/Bálványos_Free_Summer_University_and_Student_Camp

Images are from several Hungarian independent and opposition news sites:

• https://24.hu/belfold/2024/07/28/tusvanyos-2024-tusnadfurdo-kepek-galeria/?gallery=1/1/galesz_tusvanyos_mm-3
• https://telex.hu/belfold/2024/07/27/tusvanyos-2024-kepes-osszefoglalo-orban-viktor-fesztival
• I found the top one on reddit, iirc it's from a 444.hu paywalled article

Rewording your question why independent/opposition newspapers go to a place like this? Hungarian government politicians don't give interviews to non-friendly media, they simply ignore them, they only go to friendly tv channels, newspapers. Last time Orbán gave a full interview with proper questions was in 2009.

If a political journalist want to get some info first hand from Fidesz politicians, they have to go places like this, because there are no other option. High ranking Orbán friends partying there, and it's a public event, so they can go there, and randomly stop politicians, they can't run away. Journalists are usually banned from most government gatherings, this is an exception. Most of the photos taken there are of Fidesz politicians and talking heads, as you can see on the articles I linked, but most of you don't know them, so I just selected the funny and and most delusional guys