The way I see it is that GNR don't 'owe' us anything. They don't want to make music - up to them. It's not like they're taking money from us and not delivering. We're not paying for albums they're not delivering.
The other side is that it's very frustrating for people that have been fans for decades. It's made more frustrating by the carrot-dangling that's gone on for years of new material just being around the corner. That makes it feel very infuriating.
If GNR said "no, we're done now, come and see us play if you want, it'll be the same music, but there's no new stuff planned, at least for the foreseeable future" I think the dynamic would change. I think most people would respect that honesty.
On a personal level it's the chronic waste of time, talent and opportunity that annoys me. People would kill for the attention and fan base GNR have, let alone the talents of every single band member, and to just let that pass by year after year seems such a waste to me. I'm not going to ever defend that.
Ultimately though..... it's boring to a lot of people. And GNR were never boring.