I understand why this exists for regular sites – a negative score indicates that there is something wrong with the question, and if the question retains its negative score for that long then it might not be worth keeping on the site. However, on Meta a negative score – particularly when it comes to feature-request – is merely indicative of disagreement. A question can have a very negative score without there being anything wrong with the question. It might merely be a suggestion that more people disagree with than agree with. Even if the disagreers only have one more member than the agreers, the question will still qualify for automatic deletion.
This does not seem like a good system. Questions that are otherwise fine may be getting deleted just because more people disagreed with the suggestion than agreed with it. In fact, I just noticed a case where this happened. This question has 10 upvotes and 25 downvotes for a total score of -15, and was therefore automatically deleted under the policy of RemoveDeadQuestions. However, there doesn't appear to be anything wrong with the question (full disclosure: it's my question); it's just that more people disagreed with it than agreed with it. By deleting this post, the record of the discussion is lost (except to those who have 10,000 reputation).
I think it would make sense to not apply the policy of RemoveDeadQuestions to Meta questions. Or, at the very least, the criteria should be tweaked. Perhaps if a question has a negative score and no upvotes it should be deleted, as there it is more likely that the negative score is because it's a bad question. But when the question has a significant amount of upvotes it should not get deleted simply because more people voted against the suggestion than in favor of it.
(I am aware of this question which which asks if RemoveDeadQuestions applies to Meta. The point of this question is to suggest that that should not be the case.)