some of you are forgetting a simple thing. its their guild. they make the rules. they might have had an issue with botters in the past and dont want to bother with the drama again.
there is a lot of drama that follows botters. you can get banned without warning. guild feels betrayed. guild feels that you should have known you could get banned and you pretty much wasted their time and effort making you an effective part of the team. other guildies get butthurt when they cant perform as well and feel you are cheating.
if the guild tells you up front they cant allow botters in their guild, you should move on. dont waste their time. after all they pay for the game too. they want players who for some reason or another fit their expectation of a player. they want people who fit in, can get along, wont bother other players, wont skip raids because of patches, wont be in danger of being reported by others if someone gets their feelings hurt.
there are plenty of opportunities to raid while botting. friends, crossrealm, bnet, premade, trade chat.
its not your 'right' to bot in someone elses raid. form your own guild/raid and do whatever, but when you join someone elses group, you should respect their rules.
otherwise, youre just a dick. doesnt have anything to do with botting being right or wrong.