Hell no it isn't unsportsmanlike. Don't blame yourself for taking advantage of an opponents mistake
Unsportsmanlike Conduct?

In a recent game I blundered (twice!) early and found myself down a bishop with a generally weak arrangement. My opponent left open an opportunity for me to force a draw by repetition, and I took it. Based on his comments he viewed this as unsportsmanlike on my part. Was it?
In no way was it "unsportsmanlike." Was it unsporting when he took your Bishop?

In a recent game I blundered (twice!) early and found myself down a bishop with a generally weak arrangement. My opponent left open an opportunity for me to force a draw by repetition, and I took it. Based on his comments he viewed this as unsportsmanlike on my part. Was it?
You give someone a computer, access to the internet, and privacy, this is what happens. Block them and move on.

In a recent game I blundered (twice!) early and found myself down a bishop with a generally weak arrangement. My opponent left open an opportunity for me to force a draw by repetition, and I took it. Based on his comments he viewed this as unsportsmanlike on my part. Was it?
Sounds resourceful to me......

In a recent game I blundered (twice!) early and found myself down a bishop with a generally weak arrangement. My opponent left open an opportunity for me to force a draw by repetition, and I took it. Based on his comments he viewed this as unsportsmanlike on my part. Was it?
No way! Your opponent was simply bitter. You found an opportunity to save the game by threefold repetition. That's completely normal. It seems like your opponent didn't know the definition of "unsportsmanlike".

Do you have something to add? Or did you just want to bump a thread that had been dormant for 7 years?

No argument from me. I guess bumping an old thread is okay if you have something of substance to add. There should some sort of punishment for bumping an old thread just for the sake of doing so.
It's unsportsmanlike.
In a recent game I blundered (twice!) early and found myself down a bishop with a generally weak arrangement. My opponent left open an opportunity for me to force a draw by repetition, and I took it. Based on his comments he viewed this as unsportsmanlike on my part. Was it?