"This is not an offer to lend" is a disclaimer that the ad isn't itself an offer to extend credit to whoever happens to see it - you have to apply and be approved first and they don't guaranteed they will offer you any lending products at all. It's usually followed up by language like "subject to credit approval."

sure, but the OP was suggesting that "advertising" was the same as "offering" to anyone who happens to see the ad (in context of discrimination) ... doesn't seem to be usable.