The leak of the Parler content shows that they were actively moderating the platform to push it on the far right side, using millions of fake accounts with admin privileges.
So Amazon terminated their account.
The ban of Trump from social networks is a different topic, I don't think Trump has a big fan base in EU, but it's the perfect excuse to demand what many have been advocating for years now: political control of the social network decisions, given that they can influence the public opinion (Facebook admitted today that their platform was used to spread violence in Myanmar)
I have personally advocated for putting social network under public scrutiny or close their operations in EU.
I am glad that the European Union is finally taking steps in that direction.
EDIT:
Do you have a source for this? I tried googling it for ~5 minutes, but my google-fu is too weak.
The two persons you mentioned as "fairly normal republicans" had their contact information carried by an armed terrorist who invaded the Capitol on the hunt for "bad guys": https://twitter.com/johnkruzel/status/1349061894418685953
There's no misapplied meaning created from the cut either, as the final parenthetical unambiguously clarifies that the subjects of the former sentence were part of the group of subjects in the latter sentence.
Parler was the number one downloaded social media app in the app store after all. According to BBC the most popular accounts on Parler were people like Sean Hannity and Ted Cruz, who each had followers in the millions.
Of course Parler had a problem with some - maybe even many - violent people, like the Washington rioters, but it seems to me that the vast majority of Parler users were not violent people, but fairly normal republicans of the kind that are still not banned on Twitter and Facebook (like the two persons I mentioned).
Removing the hyperbole on each side, I think it'd be interesting if the EU looked into this to conclude if the shutdown of Parler was ok or not.