There is a huge difference between being codependent and having a fulfilling relationship. However, many people incorrectly see them as the same. A codependent person needs someone in their life to function but a normal person's life is just made more joyful with a partner. If being with other people didn't make us happier, then why would anyone ever do it? Relationships are hard work at times and unless it is a political power play, they aren't something people willingly go into without expecting more joy. No one thinks "geez, I guess I'm so happy that I want to bring it down a notch by falling in love". On the contrary. Do you purchase a dog because you want to saddle yourself with responsibilities? Nope, its because it's going to improve the quality of your life.
There definitely has to be a good foundation with partners accepting and loving themselves, but that doesn't mean they can't have more fun with someone along side them. It's like having a piece of hot apple pie and then putting ice cream on top. Both are good separately but fantastic together. Love can be an illicit drug just like morphine but they can both also be used properly and for good. The push to be okay with your singleness is from two things: fear and selfishness. If you convince yourself that you are happy, then eventually your head will believe it but your psyche and body will not so we suppress the impulse to find love - it's tormenting self delusion. Being single doesn't have the anxiety of possibly being hurt so instead people are kept away. Singleness also keeps you from being responsible to anything because you don't want to care about anyone but you. Selfishness usually is derived from control which is a product of fear.
Stop trying to convince yourself that it's okay to be single. Either work through your fear for a more rewarding life or at least admit that that's the reason and say "hey I'm too afraid or self centered" but please stop propagating this load of bullshit aiding people in being delusional.