Good grief, the Bible (Catholic reference book) calls them money changers....I have no idea of what they were doing nor do you....Christ was upset because whatever they were doing, they were doing it in the house of worship....He tossed them out!!
He tossed them out because they made the Temple a market place and were cheating people.
Read the account. He said they had made it a den of robbers.
Not only were they conducting business IN the Temple, they were cheating people in the process.
That’s not simply making a living. Not in my book anyway. Maybe yours is different.