I am not disputing unix philosophy. I am disputing the "if I pipe data to another program, I am not responsible for what happens" non-sense.
It's not nonsense. fetchmail's authors can't be held responsible for you not configuring your MTA correctly. And they certainly shouldn't try to check for every possible MTA configuration under the sun. Maybe you wrote your own MTA? How would they know?
They did what they were supposed to... send your MTA the data. If you screwed up the MTA configuration, and lost it after they sent it to your MTA, that's your fault - not theirs.
You learn to TEST things like MTA configurations in the Unix environment. No one loves your data more than you do, so there's no one more qualified to see if your data is intact after passing through things like your MTA than you. And testing your MTA before sending it things with programs like fetchmail is 100% your responsibility as the system administrator.
It's so much more powerful and better when you've actually engineered your solution (engineering includes a test phase, remember) to your specifications than to trust some programming guy you've never met to do all the Right Things.
Unix's building-block approach gives you more visibility into the data chain than any monolithic application could ever do, and in the process, gives you bigger responsibility to check each step thouroughly and think about your implementation carefully.
Nate