Why am I me?

[Edwardo Piet]

People can prove things in a number of ways that don't make logical sense. What you mean to say, is that 'tautology is the only form of logical proof', is it not?

Nothing that is non-tautological can exist because that would require it to not be itself which means it wouldn't exist. Logical proof is the only form of proof because proof is absolute evidence and the only absolute things are logical things (and so the only things, because relative things either absolutely exist or absolutely don't exist).