No, it's nonsense. However the adage does have a different bend if you understand it. What is really is saying is that by actively hunting people rather than passively being open to them you will run into people don't want. How to explain this...
Okay, here's your life, you work at somewhere and you enjoy your job and you have a decent social life with people about your level. You maintain this group and eventually someone will join that meshes with you and voila, "The One".
The alt version of your life is you work somewhere, enjoy it, but instead of hanging out with people who are on your level, hunt, and hunt some more, hoping to find someone on your level, and you miss them every time because you're looking at elements that you can judge quickly versus being in a group and then evolving into that relationship.
People who are actively searching for someone are frequently the type who feel they NEED to be in a relationship. If you NEED a relationship, you'll scare off the stable people and end up in tumultuous relationships with the unstable ones. People NOT actively seeking Iove are likely less needy, more independent, and more comfortable with relationships that develop slowly. These aren't the people who feel the need to define the relationship right off the bat. They are more comfortable just seeing where things go because they aren't afraid of being alone if it ends up not working out. These people repel the unstable people who will need a ton of time, attention, and validation while simultaneously attracting stable people by giving them the time and space needed for REAL intimacy to develop with minimal validation needed along the way.
The REAL lesson is that you have to be comfortable being alone before you will likely be able to meet someone and develop true intimacy with them.