Joanna Cherry, who has received online abuse and threats, said she was “very upset” the SNP's former chief whip in Westminster, Patrick Grady, received more internal support after a Commons investigation found he had sexually harassed a teenage staffer.
Ms Cherry has long been at odds with the SNP’s leadership, including Nicola Sturgeon, over her views on transgender issues and their impact on women’s rights.
She is critical of moves to allow Scots to self-identify their sex, fearing this will impact on women’s safety.
Appearing on the comedian Matt Forde’s Political Party show at the Edinburgh Fringe, Ms Cherry said she was tipped off that she was going to be stripped of her SNP frontbench role in Westminster three days before it happened last year.
"I think what I found most upsetting about it was the unfairness of my treatment,” she said, stressing other colleagues had “openly disagreed” with party policy and not been demoted.
"That was upsetting. And also the fact that there was no acknowledgement of any of the work I'd done over the last few years before.
"It was like I had been, well, I suppose, cancelled, just erased from SNP history.”
In a reference to former first minister Alex Salmond, Ms Cherry said she was “not the first person in the SNP that that's happened to recently”, adding: “But it was very upsetting and bruising."
The Edinburgh South West MP said she received "a series of very threatening messages" later that same day from a party member.
She said: "The lack of support from my colleagues was very difficult to deal with.
"On the other hand, in many ways it's the best thing that's ever happened to me, being sacked from the SNP frontbench."
She said it had given her more time to concentrate on her constituency and committee work, as well as "making it easier" to speak out.
Ms Cherry said First Minister Nicola Sturgeon and SNP Westminster leader Ian Blackford had never reached out to check on her wellbeing.
Elsewhere, she compared her own treatment unfavourably to that shown to Mr Grady.
Mr Blackford was previously forced to apologise after a leaked audio recording showed him urging colleagues to "give as much support as possible" to the former chief whip.
Ms Cherry said she was "glad" not to be present at the SNP group meeting in which this happened because there was a "very unpleasant witch hunt into who had done the recording".
Asked what she thought when she heard the recording, she said: "Personally, I was very upset actually, because it was interesting to hear exhortations of support for a colleague that had been found guilty of sexual harassment, when no exhortations of support for a female colleague who had been threatened with rape by a party members had occurred.
"I did take it rather personally, but on the broader issue I thought the whole episode was most unfortunate."