The main reason (why banks don't like btc and other cryptos) is the loss of profits.
Transactions made via blockchain kills transactions made via banks.
But the topic is essential! It should be upped!
Agree with your opinion, reduction the income of banks is the main reason underlying hatred of bitcoin. Just imagine if all the people have been using blockchain for the delivery of the money, then the banks of course the banks will experience a decline in income very drastically.
Their major problem with Bitcoin is without any intermediatory like Banks people are trading by themselves without any further commissions. This makes them more frustrating about the Bitcoin and sees without any government and banks involvement the price of bitcoin is kept increasing.