Some very strong feelings in this thread!...I agree 100 % with your point in bold, above.
Roglic is not a "leave them all in the dust" rider like Contador or Pogacar. He is an amazing TT'er (PDBF excepted, but even there he was top 5 vs specialists like dumo and wout), and a VERY GOOD climber. That is a winning formula for just about anyGT in the last, oh, 50 years. He just happened to run into a buzzsaw named Pogacar. Of course he can win, but it will take his usual strong TT, and either a team attack on UAE or a bad few days by Pog. (and it bears repeating that in head to head GTs that both finished, it's 1-1)
Should Vingegaard be allowed to go up the road if, say, he's feeling superhuman and Pog merely human, or Pog attacks and Roglic can't follow? Of course! That's the point of having co-leaders, Even Roglic would certainly agree. But, should Vingegaard drop Roglic if he's merely losing a bit of time? No way.
As for Roglic's current form: It's hard to say. In theory, he doesn't want to come in too hot, like Giro 2019. But he does need to prove that his knee injury, whatever it was, is healed. He did not look as good as Vingegaard on the Solaison, it's true. But that is a hard, hard climb, and it was very hot that day. So maybe Roglic wasn't on his best form or was feeling the heat. O'Connor came back a bit because the top 2 slowed once they got a gap, and why wouldn't they?