It is my feeling that there is more to this story, and that the OP is not giving us the whole truth and nothing but the truth
Were you maybe overweight upon late arrival to check in?
Were the staff maybe offering to help repack your luggage in order to help you make the flight in question, and not miss your connection in AUH?
Were the staff maybe hurrying you, which then in turn came across as being rude/a bit short?
What happened to the Excess Luggage you left behind?
Did they offer to let you pay for your extra kilo's they said you had?
The bagage allowance on Etihad Airways is 20kgs. If your bag were 15kgs, why did they ask you to remove items?
I am not in any way siding with the airline, however I personally believe there is more to this than meets the eye.
These are just questions that upon answering truthfully, may hold the all important conclusion to this story.