It is up to the bank if they give you an account or not. Just try next bank.
There are forums about opening bank accounts. Perhaps ask there?
DTV is not a tourist visa, it is a DTV. And on a tourist visa you easy get a bank account.
You get a bank account on visa exempt.
The guy who knows nothing is you.
Opening a bank account is a business transaction. Perhaps go into the bank with proper clothing, proper shoes a smile and say "Sawasdee Khrap" as greeting?
Otherwise bite the bullet and ask an agent. Wow, an agent can make a bank account on a DTV? So? Obviously the kind of visa is not the problem ...