I'm guessing this is due to the way they are listed by Bricklink and so I'm not sure if there is the possibility of updating things in some sort of Brickset only amendment, but here goes.
The 2011 and 2012 SH SDCC exclusive minifigures sit with the rest of the general release SH minifigures in the database, but the 2013 and 2014 ones sit as sets.
I can see why the newer ones could be classed as sets as they have blister style packaging which can be closed, rather than just being attached to a piece of card, although is there a reason why the figures aren't also listed as figures and is there the chance to updating things so that they are?
This would then also apply to others (SH and other themes) like Rocket's Warbird, Bard, Unikitty, The Batmobile (the figures are in the list, but by virtue of their appearance in the Juniors set, without then a mention of them being in the SDCC Batmobile), Azog and any others I've not thought of.
Is there any chance this could be applied?