I reasoned, I didn’t just assert that view. It is a conclusion that arises from the definition of a rational belief.
All rational beliefs are rooted in premises, all premises are rational beliefs. Therefore any rational belief - of necessity - must be based on other beliefs.
I made no claims about what these initial beliefs are or what led to them, I do not know. But if you had absolutely no rational beliefs you’d never be able to define any premises and without premises you’ll only have irrational beliefs.