I think it's a little more nuanced. Parler had some users who broke Parler's own TOS, and Parler was slow to react (problems of scale? victim of own success? Willfully slow to enforce? We don't know). Amazon acted swiftly, in light of a loosely connected civil disturbance (although Amazon's actions were not expressly a result of the riot, the timing is relevant).
Frankly I'd go further and say that not even Twitter and Parler were competitors.
Wasn't Parler a glorified WordPress comments section? That's all fine and well, but if I started a website and broke the TOS I doubt anybody would have wept for my losses in the same way.
It's really odd seeing people conflate, or even manufacture, predominant socio-political ideologies for companies and then labelling them competitors when those made-up ideologies differ.
