You are wrong. The word feign is appropriate in the context.
Correct,they pretend to speak for us.
Feign
verb (used with object)
to represent fictitiously; put on an appearance of: to feign sickness.
to invent fictitiously or deceptively, as a story or an excuse.
to imitate deceptively: to feign another's voice.
verb (used without object)
to make believe; pretend: She's only feigning, she isn't really ill.
Per those definitions, the author used the word in the wrong context.