Because he said very clearly that he’s a Republican. Here’s post #35, which appeared to be the post you were responding to:
I gave you a note for post #37 (your first post in the thread). If you were not addressing Stratocaster I am not sure why you said “you” at all. The issue would be the same if you were taking a dig at OMG A Black Conservative (who you mentioned earlier by name). You went on to address Stratocaster as “you” in several subsequent posts:
And for whatever it’s worth Stratocaster seemed to feel you were talking to him specifically:
If none of that was intended, so be it. As you said, you didn’t get an official warning. Just be more careful. In your post you said outsmarting “you” Republicans was not too hard. Two posts earlier another poster had identified himself as a Republican. So I think my reading was very reasonable.
Which makes it kind of ironic that your defense of your comment is that you weren’t reading carefully.