I think I can shed some light on that.
There was a blog on the BBC sport site a while back, the journo was (I think) a West Ham fan, but he lamented the fact that 90% of his football journo colleagues were Tottenham fans. So for starters, I'd say there is a heavy bias towards Spurs in the media, especially in London.. which of course is where most the media is. And you know how many people lap up whatever the media tells them.
I think another part of it is this particular generation of journalists are probably mid 30's-mid 40's age group. They grew up (probably in London!) in an era when Spurs were THE glamour club. When Spurs were winning trophies in the early 80's, their side included Ossie Ardiles and Ricky Villa, two of the earliest foreign imports and thus very high profile. Not to mention a certain Glenn Hoddle. When I was at school in this era, everybody supported Liverpool or Spurs - and Spurs rightly had a reputation for playing some great football. Those days are long passed, but the reputation seems to have stuck.