I've noticed this myself - I'm at a loss to explain it. My pet theory is that they're *desperate* to stop looking like the wee provincial side they are, and thus they're using their miraculous title win to try and big themselves as up a rival to the smallest of the top six, so they can pretend to be part of the big boys' club. They'd get laughed out of the room if they compared themselves to Chelsea, Arsenal, Liverpool or United based on their one PL win...but they can easily puff themselves up by imagining themselves as rivals to Spurs, since we haven't won a single one (or anything at all post-2008, really). Thus the manufactured animosity, which is simultaneously funny and pathetic given their present circumstances.
Well, either that or they just dislike that we had the gall to temporarily challenge them last year - *extremely* temporarily (like, only-when-we-were-leading-against-Arsenal-at-home temporarily). But if they held grudges based on teams competing with them, they'd have to hate the entire league given that everyone (except Spurs, predictably) has taken turns utterly rogering them this season.