I think this is the correct interpretation, he was just messing with Raiola after he called him a dog.I think theres a few ways of interpreting it, the one which strikes true to me is Raiola offered Pogba to City, most likely purely with he intent of getting him a better offer. People seem to be thinking that because Raiola offered him it means United or even Pogba offered himself. Personally I've always thought Raiola was a shifty git and wouldn't put it past him too do something like this. I don't even think it's technically that bad a thing to do, even though yes it'd be annoying if i was a United fan, but the idea of shopping a player round to increase his value/standing in contract negotiations is probably standard practice, doing it without the player knowing however.
Should Pep have brought it up? Probably not, bigger man and all that, but its a pretty good way to get everyone mad at Raiola if the offer was done behind Pogba and United's back, which I suspect is what Pep was going for
It is of course possible its all bullshit from Pep but i would've thought Raiola would've straight out denied it and frankly its a pretty outlandish thing to say if its a lie, also I guess I'd be slightly surprised he knew rail was Mikh's agent off the top of his head?
The other part where he said Pogba is a great player but they don't have enough money to buy him, seems to implicate that if he was to undertake that signing, like Raiola wanted to, he'd have to take him away from United (not cheap) and that also opens the door of Pogba not knowing the interest or even contemplating a transfer request, therefore Raiola was baiting City/Guardiola into disturbing United/Pogba on the chance that Pogba might be sad enough at United to even flirt with City, raising his market value in further contract extensions.