Hmm. Older translations say "thieves", not "robbers", and both have the same negative connotation. A robber is a subset of thief, focused on stealing from particular places and who uses aggression to get your goods, such as bank robbers and highway robbers. And as opposed to a "burglar" who is a stealthy thief who breaks into buildings. It is rather consequently described, in all retellings of the scene.
[[book:: Bible | Matthew 21:12-17, Mark 11:15-19, Luke 19:45-48, John 2:13-16 | KJV]]
You say that He thought _what_ they were doing was fine, but that He was only angry about _where_ they were doing it, but they were actually notoriously shady characters, at the time, and their transactions were partly illegal and completely usurious.


NCR
Why Jesus Opposed the Moneychangers in the Temple
The Temple was a place of worship and praise and prayer and ritual sacrifice — not a place to exploit the poor