I think some people posting here mean letting agents rather than estate agents. Some letting agents are also estate agents but a lot are not. Letting agents act on the landlord's behalf.
"Estate agent" is often used as a generic, colloquial term to cover lettings AND/OR sales. They work similarly, though, in that they 'work for' the landlord/seller NOT the tenant/buyer (though obviously it's in their interest to be professional with both!) because that is the person that pays their income.
PR, I would say you're right but native Brits moan about estate agents just as much as people from the USA that might be used to realtors (who do the conveyancing). Though as a matter of trivia, the fees a realtor makes from a sale in the USA is much, much higher than a UK estate agent due to the fact that a realtor is a one-man band and an estate agent is just one person among several who deals with the sale of a property.
In a small defense, though there are no licensing requirements (and most 'decent' agents actually disagree with this and would love for it to more towards the American way), there are various professional qualifications an agent can voluntarily achieve, in addition to the professional associations an agency can join that 'police' the industry.
Sorry not to get defensive, I just feel bad that my husband loves his job but half the time is ashamed to tell people what he does for a living.
(for reference, this thread was started to talk about lettings, though, and not sales!)