Quick answer
Strip away the accounts and the rich and the poor are the same creature: made by the LORD. One fact under every economic difference, and everything Scripture says about human dignity grows out of it.
Read both lines
The first line stages the meeting: the two ends of every society have something in common, which is news to both. The second line names it: the LORD is the maker of them all. The proverb does not deny the difference between rich and poor; it relocates the difference from essence to circumstance. Neither the money nor the lack goes all the way down; underneath both stands the same Maker's signature. The claim carries teeth the book bares elsewhere: he who oppresses the poor reproaches his Maker (14:31), and mocking the poor insults the One who made him (17:5). Contempt across the economic line is, at bottom, a quality complaint against God's workmanship.
Related: Proverbs 14:31 · Proverbs 29:13 · James 2:1–5
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.