That said I don't know much about these particular people.
AOC could be considered fairly 'far left' she's not exactly a radical.
To the OP's point, I think Parler was trying to legit be an alternative where they didn't have Jack Dorsey in charge, but I'm doubtful if they were actually looking for the holocaust denying crowd.
I suggest probably their comfort zone would have been 'Fox News'.
However, traditionally, the terms "far-right" and "far-left" have been reserved for people who believe violent government coup is a legitimate means to an end.
And lately, people have taken to calling more moderate conservatives "far-right" and "nazis" as a way to delegitimize their opinions, and make them sound beyond-the-pale.
Where I'm from, "far-left" and "far-right" means "people who think violence is a legitimate means to enact their ideology."
So that includes Nazis, the KKK, and communist revolutionaries. It does not include Rebecca Mercer or Breitbart.
Check out this data: [1]. Breitbart is only a smidge more conservative than Fox News, and Fox News is the #1 watched cable news channel in the country. That is called "mainstream." Presumably, the "far-right" would be "far" beyond the mainstream.
[1] https://www.adfontesmedia.com/interactive-media-bias-chart-2...
If he wasn't cynically cashing in, then he's not a very deep thinker either.
https://www.forbes.com/sites/abrambrown/2020/06/27/parlers-f...
They literally welcomed pro-saudi comment farms to their service as well:
“The nationalist movement of the Kingdom of Saudi Arabia has made it known that big tech is censoring them at rates we have never experienced in the United States,” Parler wrote in a post on its own account on the site. “Let us welcome them as we all fight for our rights together.”
Reminder: Saudi crown prince, Mohammad bin Salman, ordered the assassination of a US journalist not that long ago. So, in a sense, Parler is really the social network of choice for dictators and extremists.
https://www.reuters.com/article/us-twitter-saudi-politics/un...
https://www.reuters.com/article/parler-funding-mercer/social...
[0] https://slatestarcodex.com/2017/05/01/neutral-vs-conservativ...