According to the
uploading rules, the abandoned tag is only put when the game has been abandoned (
confirmed by the dev) or
the developer hasn't posted anything related to the game for at least 3 months.
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So yes, not having an update for a long time is not merit for it to be tagged as abandoned if the dev has been posting stuff about it, even if is just to say he still working on it.
And yes, it could be considered trolling, unless you have
absolute and
undeniable proof that would convince even the blindest of fans that the game is gone for good.