Pure TLDs shouldn't be marked as "non-domain entry"

Feature Requests Partially-implemented
1 
  [i] Target: https://v.firebog.net/hosts/Prigent-Adult.txt
  [✓] Status: No changes detected
  [i] Imported 4509858 domains, ignoring 4 non-domain entries
      Sample of non-domain entries:
        - adult
        - porn
        - sex
        - xxx

If i want to block porn in my network, it is very easy to block the entire top level domain.
I think pi-hole should accept the new generation of tlds (Adult Category | TLD-List )and just block them even without a second level domain in front.

2

That seems like a format or syntax glitch in that blocklist.
The HOSTS format only allows exact domains - it doesn't allow for wildcarding subdomains.

To address this, contact the blocklist maintainer.

In order to block all subdomains of those top level domains with Pi-hole, enter them via Pi-holes Domain management and tick Add domain as wildcard before adding them.to your blocklist.

5

Pi-Hole could also parse them as wildcards instead , similar to ABP style lists.

6

Pi-hole offers limited parsing of ABP style adlists which allows "wildcard" entries. However, they need to be in ABP format ||domain^.
We recently added support for pure TLDs in ABP style: Allow TLD blocking using ABP style by rdwebdesign · Pull Request #5240 · pi-hole/pi-hole · GitHub

Please note, this pull request has not been released yet.

7

No
The HOSTS format is designed for plain domain to IP address associations only - it isn't expressive enough to allow a distinction of domains that should be treated as wild cards from those that should be treated as plain domains.

If you want to use subdomain wildcards, use an ABP style list instead, but note the limitations of that format for a DNS filter like Pi-hole, as mentioned by yubiuser.