People always seem to knock success. Ironic, really, when we remember those decades of Chiefs mediocrity... 
Exactly. The Chiefs and their fans suffered for long enough.
I remember the '97 playoffs when they got jobbed by Shanarat and "Slimegate" (and also Marty Schott making his usual postseason play calls that made no sense). That was one of a series of torturous failures throughout that decade.
To me, they're fairly benign as far as sports dynasties go. Everything people are pointing to as reasons to hate them just seems like nitpicking to me.
The whole Swift-Kelce dynamic has been highly politicized. Aside from that, the Chiefs are getting the same heat that any dynasty receives. They are on a run not seen since the Patriots of the early 2010s.
I will admit I rooted for KC to win yesterday, simply because I enjoy watching Mahomes do Mahomes things, especially in clutch games/situations. He's the greatest I've ever seen play the game.
I rooted for Detroit as well. 
The Niners are a super-team, as great as Mahomes is, I don't see KC beating SF.
Oh yeah, definitely a big reason. I didn't really want to go there, but suffice it to say I take a certain amount of enjoyment in seeing the Chiefs do well given the type of people who seem incessantly whiny about the Kelce/Swift story.
As far as your last sentence goes: remember that the Ravens went into San Francisco and laid a total ass-kicking on the Niners just weeks ago. And we just saw SF play a horrendous first half against the Lions at home. It took some really awful football from Goff and the Lions' passing game in the second half, as well as some head-scratching decisions from Dan Campbell, for the Niners to get out of that game alive.
Also, the Chiefs have seemingly dialed it up to another level this postseason. They look like they're in their comfort zone again, whereas most of the teams that outshined them in the regular season have collapsed under the spotlight.
So yeah, I'm not seeing the Niners as this unbeatable juggernaut. This is looking more like a toss-up to me.
