Here's why:
* Hurriedly implies a sense of rush and potential lack of care. It can suggest that something is done quickly but not necessarily well.
* Hastily has a similar connotation to hurriedly. It suggests a lack of planning and potentially rushed decisions.
* Speedily implies efficiency and swiftness. It suggests something is done quickly and effectively, with a positive outcome.
While all three words imply quickness, speedily is the only one that carries a sense of competence and positive outcome.