2) Therefore, the president acts according to norms
3) Therefore, whatever the president does is normal
4) And if not, then Congress obviously wouldn't stand for it
5) Since they're standing for it, it must be normal
6) And of course if not the courts
etc
The meeting wasn't about the election
The Trump campaign didn't know about the meeting about the election
Trump himself didn't know
Anyone would take that meeting, it wasn't illegal
All businessmen do illegal things
In a culture of abuse, reporting the abuse is the offense.