Why wasn't former President Bush of the USA, charged with any crimes, when we marched into Afghanistan and Iraq by his orders, under pretenses?

Many factors play into this.

Lyndon Johnson came right out and told the American people that we needed to fight the Vietnam war to protect our rubber and tungsten interests there. Fighting a resource war is unfortunately not the crime it should be, and never has been.

If the WMD pretenses were false, Bush can and did blame the intelligence community that produced the information. No one there was prosecuted because it’s in their daily routine to say “we believe that inside Iraq / North Korea / etc that something bad XYZ is happening” and being wrong is not a crime.

Generally, no one believed that Saddam Hussein was good for Iraq, the Middle East, or the world. Iraqis were quite thankful for his removal. So even if the WMD thing was phony, there is a sense of “well, at least it all accomplished some good purpose.”

We can point to Bush as the sole responsible party but the reality is that Congress voted to authorize it and 40 nations participated. So responsibility is really pretty diffuse and Bush can say “everyone agreed it was the right thing to do.”

American politics are a shit show and any effort to hold a president accountable is seen as a ploy, and even if it isn’t, it becomes mired in the deep partisanship.