I don't have any issue at all with anyone making a profit. They did, after all, risk a pile of cash and waited over four years to see anything for it, so there's no issue there.
My only issue was with the obtuse phrasing that might lead an uninformed person to believe that they're selling the bike for close to what they originally paid. Quoting the price they paid for both bikes but then only talking about the new sell price for a single bike is gauche at best and dishonest at worst. It would read better if they just never mentioned their original purchase price. Why bring it up at all?
To be transparent, I say all this as someone who has three pledges, one of which I intend to resell at the best available market rate, most likely via eBay or similar.
Now as far as value goes...my life situation was very different four and a half years ago when I backed the project. At the time, 1300USD for a Ti folder that met Helix's size specifications was a STEAL to me. However, I wouldn't pay 3500USD then, and I wouldn't pay it now. Clearly at least a handful of folks are willing, otherwise they would have been unable to sell out of the "oh my god we need to show new revenue" bikes. Only time will tell how long that price will remain viable.