I myself as an agent strongly agrees that we should get paid if
1) we are appointed by the owner to assist in selling/letting of a property
2) closed the deal for that particular owner & buyer.

Owners or buyers often think that our jobs are just simple, but it actually requires some "backstage"hardwork which are not seen & unappreciated- such as, we need to conduct market studies/analysis (area studies, property values, market price ), connecting/filtering buyers and sellers, provide professional services and advice regarding the property, negotiate, write up offers and gather relevant documents for solicitors, handling a lot of adhoc situations upon signing of S&P & etc..

We worked hard, put in much effort, strive to give the best services & yet, we are also human who needs to make a living (Ethically) :)
So, yeapp, property agents definitely deserve their commissions ^^