To be honest, even if the figure of 3000 executed is accurate, while really bad, it's not anywhere near the top 10 (probably not the top 30) regimes in terms of numbers of executions. We don't have to even go as far as Hitler or Stalin, plain old Assad or Saddam would surpass Pinochet handily.
So while we can acknowledge that Pinochet was a tyrant, I think we need to put his regime into much needed perspective. I wouldn't wish anyone a life under his regime, but there are frankly a HUGE selection of even shittier dictators to choose from. Compared to them, I think we can have a frank discussion about what Pinochet did right (and he DID do SOME things right, no regime does EVERYTHING wrong) without smearing people as "sympathizers".