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.