I think they pay attention, but don't process the negative parts because they wanted Dany to be their heroine. A bit like Tyrion had done. I mean, I read in here that people were naming their kids Khaleesi, so obviously there has been some excessive heroine worship going on, and it's not surprising that some on this board did the same. Some (not all) of the posts along the lines of "the Dany I know wouldn't do this" seem like emotionally overwrought versions of a boyfriend who found out the girl he worshipped turned out to be a #####. And she's beautiful and people want to believe she's good as a result. Studies show this stuff happens. I can see why people wanted it to be different.
Maybe it's because I watched all of the show in a truncated period, but it seemed evident to me how she was going to go. I feel like it's been telegraphed for quite some time, not just this season. I give a lot of credit to the actress who plays her, because she has said so much with a subtle look or a tone change without going over-the-top into capital A "Acting." In the scene last episode where she asked Jon not to tell Arya/Sansa, she was full of emotion - crying, pleading - but when it became clear he wasn't going to agree, she did a 180 and the temperature in the room dropped 100 degrees as she adopted an icy, stoic glare and spat out her line to him. Great acting that in my opinion helped deliver the logical conclusion.