"I know Farangs have to show money and keep it there to get one - is it the same for Thais .? "
This has more to do with risk, and in other countries where you are on a temporary visa (like the Thai Non-O is still a temporary 1 year visa) you would be in the same situation - only eligible for secured credit cards. If you were a permanement resident they know that since you are here permanently - there is little risk of you leaving the country and avoiding paying off your debts. If you are on a work permit (renewable), there is less of a risk since you would have more to lose than someone on a temporary visa -- you might be eligible for a credit card after a number of years. I think you will find that you would have a hard time getting a non-secured credit card in many western countries if you were on a 1 year temporary visa (more akin to a longer tourist visa) and thus lacked both a credit history in that country and some form of permanence. (permanent residence, work visa with an indication of permanence).