You should still encourage people. Just because you don't know anything about lower tiers does not mean that lower tower pokemon are not viable in OU. What you believe sucks, has a niche and it does what is supposed to do. By telling them they're favorite pokemon sucks discourages players and takes them away from the game
Normal Gem is an item that some pokemon use to receive the unburden boost and others use to increase the power of Self Destruct or Explosion. Hitmonlee is the most notable for Normal Gem/Fake Out and Lickilicky is the most notable for Normal Gem/Explosion. Before you go saying they are bad pokemon (because you've said it before), they serve the purpose they are meant to serve. Being on Serebii, you must also remember that not everyone plays just OU. They play UU, RU, NU, PU, VGC and/or non standard rules. What is not allowed in OU or not viable works in other formats/tiers. Do not tell someone something is bad or not allowed because things work. Or for simplicity, it may be their favorite pokemon and they want to use it.
I recommend you read this.
I happened upon the thread, read the article, and enjoyed it. It was full of great points that I had some not-particularly-well-formulated idea about. And that picture at the top made me laugh hysterically! So a big thanks for that!