[ProReborn]

The issue here is you're trying to glorify and propel forward a mature community within Garry's Mod, on a game mode on a decline currently. Right now I'd say RP and TTT are in their primes. Prop hunt attracted younger audiences from the gate. Youtube is flooded with Prop Hunt videos targeted at the younger audiences. Currently, the average GMOD player is much younger than a CSGO/Battlefield player. GMOD is silly, and therefore attracts more of an immature audience.
It's not you, or staff, it's interest.
Games with mods are over saturated with prophunt game modes. COD now has servers everywhere with it, and now is supported as an official gamemode in MWR. It's player interest.
Right now if the server wants to stay afloat we need to cater to everyone.

GMOD isn't the game to ask for an "Age Gate", far too many mixed ages ranging from 10-30.