I totally get where both sides are coming from. It’s definitely a presentation problem.
I’ve even had incoming emails in the past like this. Once a site owner actually asked me to add a rel=”canonical” tag to point back to their site, which I was quite impressed with. Ultimately I just fixed my display and provided only an excerpt. My intention was only to ever provide the reposted site the ultimate credit.
These days I don’t do too much reposting at all, and if I do, I’ll highlight a snippet and then ping the Internet Archive to save a copy on my behalf so that it’s still there in the future if I want to refer back to an original.
In rare cases for things that I find highly important, I’ll also repost, but keep it as a private post on my site that only I can see as an archived copy. Other times I’ll post and also add a rel-canonical back to the original site. I’m certainly never reposting as a means of creating traffic for my own site.
It’s interesting to me how frequently these same sorts of behaviors on personal websites will freak people out when they’re daily occurrences within the social sphere where they may not have better presentation. I had an online magazine send me a take down request a few weeks back for using a photo version of one of their generic mastheads in a spot that was obviously a reply context (and incidentally met all the requirements of fair use). Sometimes you can’t win despite your best intentions–just keep trying and we’ll get there.