There certainly can be a genuine former feminist.

Some, not all, but some women out there are genuinely viciously self-serving, with zero loyalty to anything or anyone except their own selves. They could have joined into the feminist movement because it promises them undeserved money and power, and then, seeing a better ship come through, a new opportunity, genuinely discard their beliefs in favor of one that promises better personal profit, forsaking their prior feminist ideology in a genuine sense so long as the profit associated with it is less than their current gig.

Given the sheer unwarranted profits in feminism, this wouldn't happen often, obviously, but there is a niche for a lower-tier-snake to ascend by hopping sides and sticking with it. Indeed, with the lavish worship offered to "ex-feminist" women by some in the Right Wing, while the niche isn't wide or large, it is present. A massive simp market that due to their nature, "feminists" have a hard time draining, but one who disavows it would have a much simpler matter.