You are of course right about FC wanting to make money with the new server. They are incapable of fixing the exploits, or do not want to invest money in developers to do so, so they go for a cheaper and easier route which is no froobs.
Some companies use a system where they ask user for a credit card, make a small authorization fee to verify it, and then cancel the fee. Nothing is charged and credit card (identity of the person) is verified. I don’t see why FC couldn’t use the same system for froob accounts. But I think they also don’t want froobs there because they don’t use cash shop enough, and to force players to make a subscription account instead of playing froobs - they get more money that way. Another bonus about no froobs is less workload for customer support.
It may sound negative but it’s really about minimizing costs and maximizing profit. Many game studios are shifting their focus to maximum monetization and FC isn’t immune to it.