They have a different vantage point. If you are able to attain a relationship at your will, or get a hook-up either from club or Tinder, you basically have intimacy and cuddling on demand. This is what they really mean. Only find a girlfriend or a hook-up when you are lonely and need intimacy, but spend the rest of your time single because you can focus on your hobbies and entertainment without worrying about a woman. It is completely different if you are STUCK wanting intimacy and can't do anything about it. It kills you slowly and you have mental degradation. I am sure if I had past relationships I would want to be single from time to time aswell, but our realities are completely different (normies and incels) and that is why you should never take their bullshit advice seriously.