If someones friend gets mad that you kicked someone that was blatantly leaching. Then the angry person needs to tell the afk person when they get back not to screw over 5+ other people.
Emergencys happen to cause people to have to afk, but if it is going to be more then 2-3 mins the logical thing to do is remove yourself unless the group agrees to wait longer. Leaving for an extended time without telling the group is fair grounds to be kicked... that person who is complaining should also be kicked because he/she is apparently a noob for defending the person screwing over the party in the first part.
Key to this is to tell the party what is going on, if the player does not. well it is that players fault 100% that they got kicked.
I think the game should have no rights to kick you. It should be 100% in the partys hands.