I would agree with you on this, that a general "digital goods" should be removed, and individual sub-sections placed under "goods" maybe? That way if someone wants to buy illegal gift cards, they can choose that sub-section, and if someone is actively looking for cracked accounts, they can choose the section for it. In general, the banning of illegal activity should be more strongly enforced.
Both the trading of "illegal" gift cards and cracked/hacked accounts are against the rules, which you seem to acknowledge (?).
For some reason, it looks like there are no active moderators in the digital goods sub.
There seem to be 2 problems regarding that. One is more mods are required, or the existing ones need to be more active.
The other problem is that apparently they consider something illegal (and therefore against the rules) only if there's absolutely no doubt. If there's a 99.99% of chances a thread is offering illegal goods then no action is taken because it's plausible the seller is just crazy and is selling at a loss. As a result the whole section is full of illegal items.
The lack of moderators is an easy fix.
As of
October 21, 2017, if you are selling a KYC verified account, it is assumed to be hacked (and against the rules) unless you provide an explanation. This rule, could be extended to other types of items such as gift cards, or at a minimum, the seller could be required to attest he obtained the gift cards legally.
There are some legitimate reasons to sell a gift card below its face value, for example if you received it via a loyalty program or some kind of contest and you do not normally shop at the store. Some companies with very high profit margins are fast and loose with giving away credits as a way to get new business.
Despite the above explanations, it is my belief the majority of gift cards sold in the Digital Goods sub either do not exist (a scam attempt), or were somehow obtained illegally.