Even if that's true, an entire town held hostage and in a dimensional bubble in the US is not something you can keep a secret for long in a world with internet and smart phones. To say nothing of people living outside of that town who have family/relatives/business there.
There was nothing outside the bubble, all of westview was inside it, anyone who drove into it would just get absorbed, it also only took a little less than two weeks and there were less than 4000 ppl living there, not hard for an organisation like SWORD to keep it quiet.
Edit: I just recalled that the whole reason SWORD was gathering info was because to them it seemed like westview didn't exist and was a creation of wanda, but what she really did was make everyone outside of the hex forget about westview, that's why the cops from eastview don't remember that westview ever existed at all.
A friend imprisoning and torturing an entire town, unwillingly or not, with magic is something Dr. Strange would investigate. And for him to just assume it won't happen again without checking it personally is ludicrous and character assassination for someone's that's supposed to be a guardian.
Not really, she's not some rando, she's a friend, an avenger, the most powerful magic user on the planet, saved the world several times and he knows now she's remorseful and isn't causing any further trouble, case closed, there was nothing left to "investigate", which is also why he doesn't care to discuss it when he does visit.
He realises he misjudged when she reveals the darkhold.
