If we have to venture into the realm of possibilities, there are several that I can think of.

One, merit fishing, hoping that people thought their action is an act of kindness and give them merit and later on sell them.

Two, almost similar to merit fishing, trust fishing. Perhaps they hoped that, encouraged by the "successful" transaction between their alt and fake deals, and possibly the alts themselves left feedback that'll encourage members to leave similar ones, they'll farm the trust and sell them, or use the built-up trust to make a huge loan themselves which will be defaulted.

Three, and this is a long reach, attempting to steal the collateral. When there is someone asking for deal and they asked for collateral, they might went, "you go first, send me the collateral." and later never actually send the loan to the borrower. Though they do asking for escrow on their now-deleted thread, it seems that was just barks, not the bites.

Whatever that is, wouldn't the fact that they fake deals is enough to warrant some suspicion and advise people to exercise caution upon doing any deal with them?