Thank You for reply.
There most certainly are connections available for BER-BKK that do not require 15 hour stops in AUH (see below); if you booked such a connection, then it would have been cheaper than the shorter journeys in order to factor in the "inconvenience" of a long layover. With these savings, you can pay for a hotel, if you so wish.
You cannot save money by selecting a cheaper itinerary that involves an overnight stop, and then expect the airline to pay to put you up overnight.
Ok, but why client should search if there are different connections from AUH to BKK as maybe two first pages of offers in ebookers.de showed only this combinations with long stopover?Etihad is not aware what tickets are sold on their stock on web pages like ebookers and with how many hours of waiting they are?Shouldn't they give at least some voucher for food/drinks?