They come waltzing in saying that, regardless of who’s appear there. Also, DECA made it clear that players can’t just “claim” realms, especially in response to when some Discords began threatening to ban and the likes. It’s all free space, unless someone bought a key and tried popping it privately in a Ghall or Bazaar. Then they have the right to kick intruders, and so forth. Realms are different, all being public.
I recognize the frustrations of the elite running Discord runs especially in trying to find an area that won’t taint their runs (and that won’t take forever to clear), but they aren’t the only ones playing the game. I’ve seen a number guilds and Discord runs accept this already (because I ask who they are by name sometimes out of raw curiosity), but there’s always a couple that rant and rave… yet life continues.
For the record, I’m usually fine with leaving an O3 popping if the runners politely ask me to leave, but you can bet I’m joining if they weren’t. I also don’t intentionally try to ruin their runs with countering or even talking. I’m just try to act like a quiet guest.