I doubt it only comes down to fanboys, that is some people not agreeing with you. There are some metrics and rankings available. Such as UCI rankings, Roglič currently at the top individuals ranking and PCS rankings, Roglič currently at top of climbers rankings.
Anyway, currently Roglič likely is the best overall rider in the world. Giro 2019 likely made him that. Before Giro 2019 Roglič didn't put too much emphasize on the importance of the team support, GT races. Giro 2019 experience is what made him embrace it on GT races and to go from being an individual to a team rider. On previous GT races Roglič more or less tested his abilities, as an individual rider. Like that epic stage on TDF, going against Froome directly, to test if he can cope with the best on hardest stage terrains, climbing. He managed to do that. In addition, what Roglič likely realized is, he doesn't need to do that all that much, to win a GT race. Therefore, when it comes to Roglič, he doesn't necessarily need to put all the emphasize on climbing, to win a GT race. This is what his competition will likely have a hard time to cope with in the following years.
And that is something I can at least somewhat agree with. As I said. I would favor Roglic in any one-week stage race he enters. He also is a very good but in my opinion not the best GT rider.
Overall that obviously makes him one of the best if not the best rider right now.
The things I mentioned in my posts are facts. Don´t really know how anyone can argue against actual stage and GC results.
We can argue all we want about team support but as long as the leader isn´t good enough to at least follow his opponents it doesn´t matter. Jumbo obviously struggled in the Giro and lost some crucial riders due to injuries. That did not happen in the Vuelta and Roglic probably had the 2nd best team behind Movistar.
Roglics Tour 2018 was good but in the Alps he wasn´t able to follow the best. That is were he lost most of his time. He obviously also cracked in the final TT.
Roglics Giro was good as well but in the mountains he was clearly worse than Landa, Nibali and Carapaz.
Roglics Vuelta was great and he was dominant. As you mentioned. He did not need to attack in the mountains (did anyway on some stages) because of his advantage in the TT.
That still doesn´t change my overall point. You don´t need to be the best GC-rider to win GTs as long as you avoid the best opponents. As of now Roglic hasn´t beaten Nibali, Froome, Thomas or TD in a GT. He beat a 39 year old Valverde and a 20 year old Pogacar.
I am still doubting his climbing ability on the hardest Giro/Tour stages. The Vuelta climbs are different and as I already mentioned I think they suit him a lot better. Combine this doubt with the knowledge that against Froome, TD or Thomas he only has a marginal (if any) advantage in the TTs and I am hesitant to crown him as the best GC rider.
What really intrigues me about Roglic is his one day race potenial. For a GC rider/climber he has a solid sprint and it seems like he is at his best on shorter climbs. Is he a contender for Liege or Lombardia or does he lack the stamina? Is he even interested in those races?