FWIW, the hypothetical the author poses of the retaliatory company (because it's a hypothetical) isn't mediated by whether or not you do the exit interview.
Your previous company can decide to hand out false bad referral signal because they didn't like your face, regardless of whether you agree to do the exit interview. Hell, if it's the kind of folks who might give out false bad referrals, they could do it because you refused the exit interview (in their minds, you snubbed them).
Without knowing more about an employer, I don't think you can apply this "Exit interviews are a trap" concept universally.
Your previous company can decide to hand out false bad referral signal because they didn't like your face, regardless of whether you agree to do the exit interview. Hell, if it's the kind of folks who might give out false bad referrals, they could do it because you refused the exit interview (in their minds, you snubbed them).
Without knowing more about an employer, I don't think you can apply this "Exit interviews are a trap" concept universally.