I've always known about the ubiquity of Monty Python and the Holy Grail references in Western media
(especially in online forums).

It is a very influential movie in shaping western humor, especially English humor.

However, I never really sat through the entire movie.
That is, until I read a recent article topic published by the Guardian:
"Dutch PM compares Theresa May to Monty Python limbless knight"
Which is, of course, referring to the Brexit situation.

Apparently, the limbless knight is a knight who dueled the main protagonist of the movie,
and as he was no match, his arm got sliced off.
However, he insisted on continuing the duel, claiming the severed limb as "just a scratch" (he ended up losing
all his limbs).
This does sort of resemble the Brexit situation, where May no doubt tries to downplay the severity of UK's
situation.

Needless to say, the humor was lost to me when I read the explanation, so I thought, all right, fine.
It's time for me to watch that blasted movie so I won't be confused every time someone makes a reference out of it.
(Long story short, it was kind of funny, but it's not THAT funny - I laughed out loud a couple times, but in the
end I would only rate a 3/5 in terms of how I felt about the movie).

Now, English is practically my first language, so I have no trouble understanding the movie or its humor.
Overall, I would say a lot of the satire is kind of amusing, but the slow pacing and generally boring plot (boring
for me) made sitting through the entire movie quite a chore.
I grew impatient half-way through, and the only thing stopping me from quitting was the desire to understand
any references to this movie I might run into in the future.

Would I recommend the movie to non-native English speakers? Well, sort of yes and sort of no.
On one hand, moments considered classic in the movie are often bizarre situations and satire that aren't going
to be lost in translation, so if one wants to get a better understanding of English/Western humor, it's still a
good material to learn from.
Not to mention, since even the Dutch PM referenced the movie, clearly it will help if one knows about it.

On the other hand, as I said, the pacing is kind of slow and the movie is amusing but not hilarious - most actors speak in a very serious tone, no matter how absurd or irrelevant the content of what they say.
While that in itself is where the humor lay, it can be somewhat yawn-inducing if you are like me and prefer
comedy presented dramatically (e.g. John Oliver style).