There are two issues I see here. One, it's not analogous because you're talking about physical property which is not intellectual property. One might be offended because it means the person they gave the bike to doesn't value it and really just wants to get money. They could have given it directly to someone who really wanted a bike. That's irrelevant when something can be copied for free. It would be more like if you were really good at fixing bikes and showed someone how to be good at it to, and they used what they learned to open a paid bike repair shop.

Re the actual bike thing (which has nothing to do with the discussion) I wouldn't be offended if the person sold it. In the hypothetical example, I got the enjoyment of fixing the bike, apparently gave it to someone no strings attached, and he's found a way that maximizes the utility he gets out of it. What's the problem?