Slag is more of a generic word these days used in the same way as 'that hammer is gay'. Feminist rants are a tad tiresome when you spend a lot of time in university
at them.
Amy is more than sexually confident. Sexual confidence is a good thing. Knowing who you are etc is a good thing. However, this is a family show (I think they should drop that tag and aim slightly more mature but whatever) and people don't want to have to explain to their kids why a woman who is in a relationship is flirting with another man. And she is doing it even though her boyfriend has met the new man.
Think of it in purely childish terms. The way kids get taught life. Man loves woman, woman loves man, they get married and love eachother forever.
Then on a show aimed at that age group you have. Man loves woman, woman says she loves man, woman flirst aggressively and sexually with man 2, man 1 is now confused and parents are having to explain things they probably can't be bothered doing on a Saturday night.
"I'm a screamer" is something that can be taken two ways so works perfectly, like the original Shrek film etc. However, Amy is a lot more 'physical' about her flirting. She was also introduced as a kissogram which is something quite hard to explain to kids, especially as, yet again, she is in a relationship.
As I said earlier, I like that she is putting it out there as we get more o her
but you need to think of the age group this show is aimed at.