but before RBF there was more trust of zero confirm compared to post RBF times
Exactly. Trust.
Not verification. Whatever happened to "Dont' trust. Verify."? Accepting zero confirmation transactions was
always based on trusting the other party not to double spend the transaction.
again RBF has made it much more easier to double spend, it used to be safer. but now its not safe
It has only gone from unsafe to very unsafe. It was never safe.
And before you rant some more about certain "people" trying to change the protocol, let me just quote Satoshi on the subject:
As you figured out, the root problem is we shouldn't be counting or spending transactions until they have at least 1 confirmation. 0/unconfirmed transactions are very much second class citizens. At most, they are advice that something has been received, but counting them as balance or spending them is premature.