Ik this is about me, so I'm gonna let others respond, but I thought I'd rewrite this for you so it's easier to follow.
Supposition refers to an uncertain belief. This means that claiming there is no reason or explanation for things is just as much a supposition as asserting that there is a reason.
When we say that there is no "why" or reason behind events, we carry the same burden of evidence and explanation as when we argue the opposite. Thus, stating that there is no reason for things does not diminish the validity of any supposition. Both positions—whether something exists or does not exist—can be seen as based on metaphysical assumptions.
Otherwise, would you not also suggest that scientific theories aren't worth our time and energy to consider? If scientific theories are indeed rooted in metaphysical assumptions, does that mean concepts like the Big Bang theory are not worthy of our attention or contemplation?