I agree that this answer may sound insulting to some, because it is just not reasonable. It's no better than "drink this gipsy love potion". Yet it has some value, which I can extract to this: love will find you, when you're ready for it. This gives a lot more ground to work on.
Short answer: this.
Long answer: when people say "don't look" they mean "don't obsess", but they don't say that. They say don't
look. Now I don't know about anyone else, but I'm firmly convinced that if you don't keep your eyes open opportunities can, and generally will, pass you by.
And if by "don't look" people mean "don't obsess" then yes, they're right. Obsessing will make you desperate. Desperation will magnify setbacks. It'll make you feel as if you are to blame when nothing materializes. It'll reinforce negative self imagery and people will pick up on that in their dealings with you. It'll make you try harder, too hard, and that will turn people off, turning the whole thing into a self fulfilling prophecy.
You lose sight of the fact that what you're looking for is someone worthy of sharing everything with. You'll be so caught up in finding someone, anyone, so caught up in impressing other people, that you fail to realize that
they should just as much be trying to impress
you. And then even if something does happen, it's probably not going to end well unless you catch a very lucky break.
So, you can't obsess. You need to love yourself before you can expect anyone else to love you, feel good about yourself, and that will make you desirable to others. When you feel good about yourself you'll be less caught up in trying to impress those people and more in assessing whether they're right for you or not. Create an upward spiral of positivity, not a downward one of negativity.
But once you get into that upwards spiral there's no reason you shouldn't
look. The only reason why this - in my eyes - semantically wrong dogma has such a following is because most people can expect to meet lots of random people of a gender and sexual preference without trying. If for some reason you don't meet many people who have basic compatibility like that then sitting on your thumbs waiting for "fate" to cut you a break and toss someone into your lap is of course idiocy.
I'm a lesbian. I don't really meet gay girls in my daily life enough to be able to rely on finding someone by chance. Even if I do meet one it's not like we have a secret dyke handshake we can exchange, so I probably will never even know if that cute girl across the way is into girls too. So yeah, I'm looking, if by looking you mean "trying to meet people and then assessing whether they're compatible at all".
If by looking you mean "being obsessed and desperate", then no.
TL;DR: That adage needs to be rewritten to "don't be desperate" or "don't obsess", not "don't look".
