Did you really just attempt to make an argument that an i68 tank should not participate in AK unless they are i70?Ok let's talk about this for a second. You ran AK to complete you relic quest on a class that you were [1] completely outclassed by the damage dealers (to use your own words), [2] and probably inexperienced with because it wasn't your main job (even if you know the rotations by default your going to be less skilled than most [i say most because there are some people out there who are so bad they should just stop playing] who plays the job as their main.
You have a monk who is most likely much more geared than your paladin so why not collect myth gear or a primal weapon before switching jobs so your not a liability to the rest of the group. People in this game are very selfish. Your going in to a dungeon where you know your going to have trouble and place the rest of the group at a disadvantage. So instead of working to fix the problem you say to hell with it, other people will just have to suffer because I'm selfish. Now for those who are fresh 50s they don't have the luxury that you do. They can't run primals to get an easy quick primal weapon. Another factor that helps to prove my point. You can craft your own ilvl70 gear. Therefore there is ABSOLUTELY NO EXCUSE to be anything less than ilvl 70 when you hit 50. Once again you prove that yes in deed you are a bad\lazy\selfish player.
My last point is regarding your scenario. While I can't say for certain because I wasn't in the dungeon, it's entirely possible that even though you marked which DPS to kill first you were probably attacking the wrong target. When I switch to a DPS job I can't tell you the countless number of times I've seen a tank not attack the summoner adds first. If your not killing the summoner first chances are I'm going to kill it first regardless of which boss your attacking (same concept with bees and bombs). So again, I wasn't there and can't say for sure, but if your not attacking the right target the dps will assume your stupid and attack the right one for you.
While I agree that ilvl 68 is adequate for clearing Amdapor Keep you also have to remember that this game has been out for quite some time now. Usually the only time someone will run AK, is if they get it through roulette, or they are completing a relic quest. If you only needed the quest for your relic and you obviously know your going to be worthless in the dungeon why not get your friends to run the dungeon with you. This IMO would be the polite thing to do instead of being a selfish liability for the rest of the group.
TLDR Yes you are a bad tank...get better gear and try again
Are you serious?