Players do expect random teams in random bgs. They’re not expecting to face premade raids on voice chat.
Blizzard did try to keep random bgs random.
https://www.bluetracker.gg/wow/topic/us-en/7200052820-joinbattlefield-post-51-part-2/
Sadly, the known PvP devs, who communicated with players and did take actions against premade raids, have left Blizzard.