First ... Wow! That's a pretty important thing to leave out! But even so, your argument is still wrong.

The Bible doesn't say that wine coolers contain alcohol, but they do. So the absence of a claim in the Bible doesn't mean it's false.

And even those who believe the bible is the only inspired word of God believe that passages have to be interpreted, often in ways that contradict what they explicitly say. For example, "I do not permit a woman to teach or to have authority over a man, she must be silent." And "Slaves, submit yourselves to your masters with all respect, not only to the good and gentle but also to the cruel." I hope you don't argue that those things mean precisely what they say and are binding on all who believe the bible is the inspired word of God.

The evidence still suggests that other sources make the trinity a consistent theme and the bible does not provide any explicit or clear rejection of this theme such that it would be reasonable to interpret it as explicitly rejecting the theme.