Banks will traditionally be against anything that has the potential to affect their business. Traditional banks have been against even fintechs because they reduced their customer base, cryptocurrency has the ability to also affect the customer base of these banks that is why they are against it.
They hate it but in reality they also benefit from fintech. How?
They steal the ideas and concepts related to fintech. They have started adjusting their services to keep up with fintech and it has only made theirs and our lives better. Soon enough they might also start using blockchain mechanisms. They are definitely looking for ways to improve on their methods somto as not to lose customers.