In fact, I think we could make a hecka long list of the self-mockery gags in this episode:
- "Fluttershy made them mad: FLUTTERSHY!"
-

"I think they broke my record for most stuff broken in under a minute. I mean, they even broke the trophy!"
-

"Pretty sure that's what fur's always for"
- "Why are your eyes darting around like that?"
- Pinkie driving ponies in harness (we've seen it before, but it counts)
- The panic-themed party

- "Falling Pony Ravine"

- The elision of Pinkie's whole odyssey, especially the Beatles thing, good lord
-

"I can't tell if my eyes are open or closed!"
And really, when you look at the yaks' behavior, it's chapter-and-verse cartooniness. I kind of think we've all been so immersed lately in hand-wringing over representation and stereotypes and so on (and maybe spoiled by stuff like Steven Universe) that we're perhaps a little quick to jump on a simple silly non-specific "funny barbarian tribe" gag for failing to armor itself in
enough surprising subversions like "cries at piano music" and "overly sensitive to vanilla extract balance". The writers were clearly conscious of the kind of minefield they were venturing into, and they're not blind to having been responsible for shit like the buffalo before, so they gave it a pretty creditable effort, like the aforementioned twists and also naming the leader "Rutherford" instead of making them all llamas so the leader could be "Dolly" or whatever. The result is a thing we can laugh at
because it's the kind of thing cartoons do, which has made a really honest attempt at not offending anybody in particular, leaving only a sort of vague buzzing feeling that we ought to be indignant about the mere fact that they're "barbarians" from an "istan" who smash up the place at the slightest provocation. Even though that's the whole source of what makes them funny.
This is the point beyond which it really starts to get stifling to a cartoon writer, whether it's admissible
at all anymore to do a thing like this, and if not, what do you do instead? I'm sure they'd be able to come up with something, but we've got to still allow ourselves to laugh at the things that we have traditionally laughed at
just because they trigger our deep-rooted "this is an absurd thing about humanity" instincts. Call it tribalism or parochialism if you want, because that's what it is, and maybe don't even defend it—maybe all I'm saying is we shouldn't be expecting My Little Pony to be the vanguard of next-generation social consciousness more than it already has been (buffalo/Zecora/Steven Magnet, I'm looking at you).
I dunno, the stream of consciousness kinda got away from me there, and I'm not sure I mean any of that. Point is, I laughed a lot at this episode, and a big part of it was that the yaks felt like a hilarious throwback of sorts, funny because of how out-of-place they are in the modern social landscape as much as because of NOT PERFECT YAKS SMASH.