You're parroting nonsense again.
Across the whole planet, the Holocene Cimate Optimum was cooler than today. The sleaze your fudgemasters attempted to pass off, yet another time, was to present a single spot and pretend it represents the entire earth. It's one of their staple big lies.
Antarctica was warmer than today during the HCO. The world as a whole was cooler. Here's the whole earth graph. Note where 2004 lies, above the HCO.
Why did you leave out the explanation of your graph?
"Because of the limitations of data sampling, each curve in the main plot was smoothed (see methods below) and consequently, this figure can not resolve temperature fluctuations faster than approximately 300 years. Further, while 2004 appears warmer than any other time in the long-term average, and hence might be a sign of global warming, it should also be noted that the 2004 measurement is from a single year (actually the fourth highest on record, see Image:Short Instrumental Temperature Record.png for comparison). It is impossible to know whether similarly large short-term temperature fluctuations may have occurred at other times, but are unresolved by the available resolution. The next 150 years will determine whether the long-term average centered on the present appears anomalous with respect to this plot.
Since there is no scientific consensus on how to reconstruct global temperature variations during the Holocene, the average shown here should be understood as only a rough, quasi-global approximation to the temperature history of the Holocene. In particular, higher resolution data and better spatial coverage could significantly alter the apparent long-term behavior (see below for further caveats). For another estimate of Holocene temperature fluctuations, see: [1]
While any conclusions to be drawn from the long-term average must be considered crude and potentially controversial, one can comment on a number of well established inferences from the individual curves contributing to the average. First, at many locations, there exist large temperature fluctuations on multi-centennial scales. Hence, climate change lasting for centuries appears to be a common feature of many regions. Assuming the timing information from these records is reasonably accurate, it appears that in many cases large changes at any particular site may occur without correlating to similarly large changes at other sites. Secondly, it is also notable that different locations appear to take different amounts of time to reach typical Holocene conditions following the last glacial termination. Scientists generally agree that warming concluded in the far Southern Hemisphere earlier than in most other regions. In part, the prolonged climate change may be related to prolonged changes in sea level, which took till roughly 6000 years ago to reach near modern levels. Some of the differences may also reflect timescale uncertainties."