I have seen :) and felt it as toxic. I also don't believe it is inherently toxic.

The surprising part to me is that I have an old pamphlet from Hayes that has a catalog of emoticons as we used to refer to them. This means that :) has changed its meaning in a generation or so... which I never considered that "pictograms" could do that.

It could also be that the context sets the tone and the emoticons are nuanced.