I would if I thought it was a bug. But I don't. First of all, you need an Apple ID for home sharing. It doesn't suffice with being on the same network and just enter a password in iTunes that you then enter in any device that wants to connect to the iTunes library.
Since an Apple ID is required, they most likely want to verify that the Apple ID is valid themselves instead of letting iTunes do it.
I checked that I can play purchased videos on the Mac that they were downloaded on, without an internet connection. So that Mac knows that it is allowed to play the video. There is no need to check whether the Apple ID and password are valid (through the internet), all that is needed is to check that the Apple ID and password are the same that were used on my Mac.
So what happens is quite likely what the programmer was told to do, but it is still a bug. And if nobody complains, it will never change. That's why you should complain about every little problem on www.apple.com/feedback, so that it has a chance to be fixed.