Valve recently made some changes to restrictions on gifting of VAC supported games, a move that is actually upsetting legitimate players. Here is what a recently updated Steam Support page has to say about these new restrictions.
Permanent Bans and Gift RestrictionsValve Anti-Cheat Technology (VAC)
Many games on Steam utilize the Valve Anti-Cheat System (VAC) or third party anti-cheat technology that can result in cheaters being banned from secure servers for multi-player games. You can learn more about VAC here. VAC bans are permanent.

Game Bans
Game Bans are used by game developers to address malicious behavior that falls outside of VAC detection. Game bans are determined by the game developer; they can range from single day bans to permanent bans. You can learn more about Game Bans here.

How does this affect gifting?

The part that has innocent users upset is the line that reads, "if an account has directly gifted a game to other players who have been VAC or permanently Game Banned, then that account will lose the ability to gift that game." On one hand, this will prevent repeat offenders from having a non-cheating friend gift them new copies of games after they've been caught cheating, thus allowing them to cheat again. On the other hand, this catches innocent users that may have gifted a game to a friend in the past without knowing that friend would one day cheat and be VAC banned. This restricts that innocent user from gifting that game out to anybody else simply because they were nice to someone. This is the part that has some users up in arms over this change.