bard has a knock back?
i dont necessarily think its rude. ignorant or selfish more likely. selfish because the skills used to do this are off the global cooldown, so they can be weaved for more dps to the individual using them. though people using them neglect to think how this impairs other peoples dps and possible interrupts in others rotations due to kiting or line of sight, which is where the ignorance comes in.
as for summoners with garuda egi on sic, thats just laziness