How can people actually think that Dany was always a crazy megalomaniac with a god complex from the beginning; that she was always exactly like Viserys and her father? She's always had a compassionate streak to her, do people really think she did things like sparing Mirri, liberating the Unsullied and other slaves, locked up her dragons because they killed a child, etc, because she wanted good PR? She has a ruthless streak, sure, but the issue people have is that the buildup to this was far too rushed and forced.
I am not a Dany stan by any means, and back in the day I used to argue with people who believed Dany could do no wrong and was a perfect saint. But to say she was always the Mad Queen from day one is excessive. That's a conflict in her character, between the good and the bad; if you say that Dany was always an egomaniac and deny that there was anything altruistic in her character, then you're getting rid of that conflict. In which case I perfectly understand why you'd like this development, because for you it wasn't a development, it was something she was always going to do. Which of course runs counter to what the showrunners are saying themselves, they believe this is a turn too; I just don't think they did a very good job at showing it.