The XEmacs fork I mentioned had some bad feelings attached. As far as I know the other examples I mentioned (Stackless, swap-to-NFS, LuaJIT) don't. But it doesn't matter what authors think. What matters is what helps the users. Would you ask for Newton's approval before calculating a planetary trajectory, or Kalashnikov’s before designing an automatic rifle? Their achievements matter precisely because they empower everyone, for better or for worse.
Emphasizing authors’ feelings in this way has the effect of diminishing their software from a contribution to the intellectual heritage of humanity to merely a service like delivering a pizza. Don't forget to tip your waiter!
Of course you should be nice to authors if you interact with them. But the whole point of open source is that you don't have to interact with them unless you want to.
Actually I agree, I wasn't trying to emphasize their feelings as much as question if there is really such a thing as a friendly fork. In reality it shouldn't matter and the concept be void, if someone forks your project and it is successful you should be glad you don't have to anymore and can do something else, as well as benefit from the improved software.
If you like what they added, you can merge it into your version unless they chose an incompatible license for their work. (That's one reason the GPL is so important: it prevents such incompatible licensing.) So if the forks continue unmerged, it likely signals some kind of difference of opinion: perhaps over technical quality, perhaps over tradeoffs, perhaps over licensing. The humans frequently turn such differences of opinion into chimpanzee factional dominance games similar to football, but in principle there is no need for that. I don't know of any LuaJIT users denigrating the hygiene and ancestry of PUC-Lua users, for example, nor vice versa, but surely it has happened on one occasion or another.
Fighting over "who gets to donate their time for free" is absurd. Unless you are one of those pretend open source companies that sell commercial versions and prevents certain cloud based usage.
Emphasizing authors’ feelings in this way has the effect of diminishing their software from a contribution to the intellectual heritage of humanity to merely a service like delivering a pizza. Don't forget to tip your waiter!
Of course you should be nice to authors if you interact with them. But the whole point of open source is that you don't have to interact with them unless you want to.