1. Everything God has decreed is for His glory. How one individual's election and another's reprobation may function as means by which God's glory is manifested is a separate issue. Even if the answer to this latter question is one which pertains to God's "secret things," it begs the question to state that a counter-factual world - one in which all are elect or whatnot - would more greatly manifest God's glory. This is a sufficient defense, if not a comprehensive one.
2. The question seems to presuppose an infralapsarian-like position in which Joe and I were at some point considered by God without respect to our elective states. If I'm not mistaken, asking this to a supralapsarian would be rather like asking a bachelor if he's stopped beating his wife.
3. Throw a variation of the question back at the questioner, which will help him see the validity of response 1 and shed some light on whether or not response 2 is appropriate. E.g. On what non-arbitrary basis did God decide to make me a male? Can the fact that I am a male be abstracted from who I am? If not, why can my elective status? Etc.