Why does everybody pretend that Bette Midler DOESN'T sing flat and often off-key? I just don't get it.?

I have nothing against Bette Midler. Her stage presence is always impressive. She's fun and likeable. And I personally think she's a really good actress. But seriously, she sings off key, just listen. She sings flat sometimes and everyone ignores this fact. What's the deal? Is there some sort of secret pact not to tell her???