Comparatives (-er, -est, less, least, more, most) can only modify a single adjective at a time. More good is comparable to good, less good, best, and not good at all, but it has as much to do with less evil as it does with less purple or less hungry.
Try substituting "positive" and "negative" (in their numerical sense) into your example:
more negative < negative < less negative < 0 < less positive < positive < more positive
Notice that the next thing after less [x] is not more [y], but less [y]; and more importantly, notice that those are all strict inequalities: something can be as less negative as it wants to be, it will still not be positive.