This wasn't put into the concrete after the fact, the concrete was poured around the post. Very common although normally centred. Basically there are these wide cardboard tubes that you can buy for this. To do this they dug a hole, put a cardboard tube in kindof like what's in a to roll, placed the post inside the tube, poured concrete in and let it cure.

This is correct. I'm amazed that so many people think a person would waste so much time and effort to just drill down into that tube of concrete so close to the side without it crumbling to bits.

There's no wood set in the concrete. If you look closely the wood stops and what's in the concrete is a metal pole. This pole was set in the concrete when it was wet so the person you're replying to is correct.