Disagree with you. I know most realtors or should I say real estate agents are under
contract with the seller. I believe they are under no obligation to the buyer.

I would and have apporached the seller of property with out holding the hand
of the agent. No harm ,no foul. If the seller tells me all comunications must go through
the agent. No problem, thats the way we play it.
At that point I get a buyers agent to collect some of the commision. If I already have a deal
in the works, they make easy money. 

To the OP -- The listing agent has only one thing in mind--Commission-- He could
give a rats azz about you or the seller once the deal is done. 
That is my opinion---and I happen to be an expert on My opinion. 
BTW I do have a low opinion of realtors in general.

Your opinion may vary, according to past experiances