Is sending an offer of $20 to someone selling an Argus C3, listed for $200 BIN, considered low-balling?
Sometimes (well, a lot of times) people list stuff at ridiculous prices, and then complain when people "low-ball." Just last week I contacted someone who had a camera for sale on a Facebook ad which they had received no interest for, and offered 1/8th the price, as I thought that's what it was worth and was willing to pay that. They came back at a bit more, which I agreed to after inspecting the item. That's how it works. If they said no, then fine.
If you find it troublesome, put a minimum offer on your "Make Offer" sale and you'll never get a "low-ball" offer again. That said, I've seen $500 items that auto-rejected offers at $475...so at least be realistic.