To me, poker boils down to three things: Statistics, observation, and deception (wasted on the unobservant).

That being said, playing hands like 74o still fits into this.

You can raise/re-raise with 74o if you think (based on your observations) that your opponent probably (based on statistics) will have a hand that he will fold to your raise.

You can even call raises with 74o to give a false impression (deception) that you play hands like this all of the time and are very loose.

It all comes back to math/statistics. You just factor everything else into the equation, but it's still an equation that's all about +EV.