With regards to Belgium: the colonial museum has been revamped, schools teach what happened in the Belgian Congo, and no one's going around defending or idealising King Leopold who presided over the worst atrocities. Belgian nationalism barely exists, so that hasn't been a thing in living memory anyway.

Also, what happened in Congo was widely derided even at the time:

https://en.wikipedia.org/wiki/Casement_Report

In Northern Ireland, during the troubles, 28 unarmed civil rights protestors were shot (14 killed) on Bloody Sunday, by the British army. They covered it up then, lying that the soldiers had been shot at and that some of the protestors were armed. That was back in 1972. None of those soldiers faced any charges until 2016. And to this day none have been prosecuted. Similarly there has been no charges levied on anyone that put those soldiers there that day. Even though that same battalion was guilty of killing 11 civilians in the Ballymurphy massacre just seven months beforehand and of brutalizing protestors outside of Magillian Internment camp a week beforehand.

Over 50 years later and there are still British MPs that fight bitterly against any British soldiers facing any prosecution for crimes they committed in Northern Ireland against British Citizens.

The Tienanmen square massacre was way worse, no doubt. But don't fool yourself into thinking that any country, especially those that colonized large swaths of the planet, have a clear conscience.