Recycled,

The oil holes in the rod ends, as I understand it, are not to let the oil out. However close the rod fits are at the crankpin and piston pin, there is a change of clearance due to operating loads. At the very least, at direction reversals - around TDC and BDC - oil can be drawn into the bearing surfaces. As the pins migrate from loaded against one 'side' of the bearing to the other, they can pump so as to draw ambient "stuff" into the bearing spaces.

These bearings are "dry sump" lubricated in a dense pressurised mist of fuel and air during the downward 'base compression' phase. There isn't likely to be a significant 'oil-slinger' effect from the enclosed face of the crankweb; the rod swings across that volume, too, remember.

Oil delivery is important. I can't place the reference just now, but I recall a discussion of why rear rotary valve engines almost always have the air/fuel inlet path off-center from the shaft center. It may have been that the rod, sweeping across the chamber, obstructs the incoming charge less when the path is offset while the valve is open. In that case, if it were sweeping 'open' past the valve 'window' when open, it may even enhance delivery of fresh charge for the next ignition up top...

So, most rear rotary valve 2-cycle, single-cylinder engines use a disk, driven by an extended pin on the crankshaft, with its port window to one side from the shaft center. Centered drum valve engines have been developed, but apparently, offset inlet flow path has proven better.

(edited to add) The accelerations on the rod and piston are very heavy. Occasionally, I understand, a thin hole has been drilled through the length of the rod, from one oil hole to the other. As the accelerations reverse direction, oil drawn into the bearings also enters this lengthwise drilled volume. The pumping is easier to understand, here, as oil in this 'channel' tends to continue in its - say - rising direction as the piston reverses its direction past TDC, and inject pretty high pressure oil to the pin bearing. ...Same, vice versa round BDC...

(For an insight to the accelerations on the piston, and much more, find Gordon Jennings' Two Stroke Tuners' Manual, available on-line, which is about 40 years old, but still pretty much the ultimate word for what goes on in our engines...)