Originally a
psychological term indicating an empowered, self-reliant individual, this has evolved through misuse into a neo-antonym of 'reactive', and is used as such to emphasise the preferability of one attitude or course of action over another. It connotes alertness, awareness and preparedness, and seeks to dispel any conceivable impression of
incompetence.
'Proactive' is interesting in that it is perhaps the classic example of the
unnecessary neologism. It serves as an antonym to 'reactive', yet 'reactive' is itself the antonym of 'active'.
Arguably, since 'proactive' is now perhaps more widely used than 'active' for the specific purpose covered by the newer word, 'proactive' must be recognised as a legitimate word. The cult of hatred that has understandably grown up around the word can only help it endure further.