Yes; criticism delivered with no justification is often simply rude. Perhaps you have a point--it's hard to tell: you didn't make one.

I said that OP had reimplemented something that already existed, but with fewer features and tests. Or did you get something else out of those six words?

You have _now_ made that statement. Previously, you merely stated that they had done a poor job of reimplementing syslog without explaining why--this is the sole component of good criticism. Implicit meaning is tantamount to no meaning at all.