Are they offending anyone?

I assume some of the original posters aren't too happy that someone's making money off of them.

Are they doing anything illegal?

Not technically, but then again, "not illegal," is the bare minimum of what we expect out of any content creator.

Can reading some people's public comment be classified as 'stealing'?

I'm not a lawyer, but considering they're making money off of reading someone else's content, I'd say it's arguable.

Do they affect you in any way?

I find the frequency they pop up in my recommended to be incredibly annoying. I also find it personally objectionable content for the reasons I've stated above, so the fact that it's so popular and it's presented to frequently only enhances that irksome feeling.

Do they affect anyone in any way?

I'd assume so, if not for the same reasons I listed then for reasons of their own.

What is so frustrating to you about it?

Everything I've said thus far.

Well, aside from feeling 'less elite' after more people learn about Reddit.

Well, aren't you a pleasantly condescending chap.