Not sure that I agree, as someone just about to let out her abode and rent. Letting agents quoted me between 5% and 12% management fee, with various other optional charges. I would prefer an independent third party to do an accurate and objective invoice in case of any dispute at end of tenancy. And I would certainly want to know that a new tenant had the means to pay, that this was likely to continue to be the case and that they do not have a track record of defaulting. All this checking involves work. DH once rented his house out while he was working abroad and he had a tenant that stopped paying... Not easy if you have a mortgage to pay. The alternative to various fees is that the landlord bears all the costs - and they will only pass on in increased rent.Landlords may be letting out their only home, or their only investment and are entitled to get a return on their investments. Of course charging extortionate fees is wrong - but charging all fees wrong - no, I'm afraid that they are legitimate businesses and are entitled to make a reasonable profit.
Agreed JessM - how can one sign a petition against al legitimate business that you have a choice to use or not use. If you think the prices are too high, be your own agent and on your head be it, surely.