Plans for the parade were widely shared on social media this week, despite no date yet being set and no permit being granted by the city council.
Organisers – a newly-formed group calling itself Super Happy Fun America – suggested the event would be a chance to celebrate being heterosexual.
They have already had to remove photos of Brad Pitt from their website after the actor, who had not given permission for his image to be used, threatened legal action.
Now questions have been raised over the past political activities of the trio of men behind the group, John Hugo, Mark Sahady and Chris Bartley.
Mr Sahady and Mr Bartley are both heavily associated with Resist Marxism – a loose ultra-conservative group found to have links to white supremacist organisations – while Mr Hugo ran, unsuccessfully, for congress in 2018 with an endorsement from the same group.
Mr Sahady is also reported to have organised a right-wing Free Speech Rally and Rally for the Republic, both in Boston, in the aftermath of the infamous Unite the Right march in Virginia, in August 2017, during which a counter-protester was killed.
Attendees at both Mr Sahady’s events were vastly outnumbered by counter-protestors.
Another rally the software engineer led in Providence, in Rhode Island, attracted just a few dozen people – some wearing masks in an apparent bid to hide their identity.
He is also reported to have marched with members of far-right groups Patriot Prayer and Proud Boys in Portland in June 2018 – an event which descended into such violence police in the city officially labelled it a riot.
And in January this year, he and other Resist Marxism associates led a counter-protest against the Boston Women’s March, which descended into a fracas, reports David Neiwert, author of Alt America and a long-time observer of the US right.
Resist Marxism, itself, does not have members—its leaders organise events for anyone who wants to go along – allowing it to have become a nimble unofficial meeting hub for nationalists and white supremacists.
Speaking after news of the proposed Straight Pride rally went viral, the Mayor of Boston Marty Walsh confirmed permission had not yet been granted for the parade but wrote on Twitter: “Permits to host a public event are granted based on operational feasibility, not based on values or endorsements of beliefs.
“The city of Boston cannot deny a permit based on an organisation’s values.”
But he added on Twitter: “Whatever outside groups may try do, our values won’t change.
“I invite each and every person to stand with us, and show that love will always prevail. Join us in celebration this Saturday for the @bostonpride Parade and in the fight for progress and equality for all.”
Mr Hugo, Mark Sahady and Mr Bartley did not immediately respond to request for comment from The Independent.