My experience with these trolls is that they not only do "PR work" or propaganda; they actively attack people who disagree with them, using very nasty language and smear tactics. That's something that "public relations" specialists don't regularly do.
Their modus operandi is not to convince people by the force of argument; their goal is to frustrate people who disagree with them and make any reasonable discussion of Russian policies impossible. They make excessively exaggerated claims; it is hopeless to refute those claims by reason because their goal is not dialogue at all, but to make all discussion about Russia obscure and distrusted.
If they manage to destroy trust in any regular media or reasonable discussion partners, they have achieved their goal. And that works quite well.
To For Russian Trolls (or Russia Today) to succeed, they don't need to be believable. It is enough if they make all media not believable so that no one trusts anything, even good sources.
Their modus operandi is not to convince people by the force of argument; their goal is to frustrate people who disagree with them and make any reasonable discussion of Russian policies impossible. They make excessively exaggerated claims; it is hopeless to refute those claims by reason because their goal is not dialogue at all, but to make all discussion about Russia obscure and distrusted.
If they manage to destroy trust in any regular media or reasonable discussion partners, they have achieved their goal. And that works quite well.
To For Russian Trolls (or Russia Today) to succeed, they don't need to be believable. It is enough if they make all media not believable so that no one trusts anything, even good sources.