Interesting Theory about who to date

One of my guy friend has this theory about who to try to date.

He said that he always try to date gals who are already attached.

Reason being:

There is only one competitor.
If the bf is neglecting in any little way, he will stand a good chance.

About gals who are not attached:

He said that they are either

1) not so good
2) too many competitors
3) not interested in becoming attached.
4) too idealistic in choosing.

Hmmm.. any comment about his words??