Removing EXP from dungeon critters?

[FrejyaAthenes]

So, after reading this thread, not a single person gave a single good reason for WHY first room farming was bad in the first place (assuming it was done through PF with a group that expects it).

Can no-one provide 1 solid reason for it?

All I could get was one story about a tank leaving after the first room, but honestly I took that as an issue of poor communication than anything else.