Why are UFOs only seen in the US?

Your premise is garbage. A few moments worth of searching:

Sorry I meant almost all the videos are from the US.

Same reason soup is only eaten in Italy.

Lol
I mean that's only on a technicality because you can only call it soup if it's made in the Soupini region. It's the same damn thing everywhere else.
- Everywhere else it’s minor stew

They're not really. In fact, UFO sightings are more evenly distributed across the world than tornado sightings.

Real question is, why are there no UFO's ever seen from Disneyworld? Quite generous of UFO's to respect designated no-fly zones.

It would be weird if tornado sightings were evenly distributed around the world given that they don't occur evenly around the world :)
Even aliens are afraid of The Mouse.
Real question is, why are there no UFO's ever seen from Disneyworld? Quite generous of UFO's to respect designated no-fly zones.

They’re painted “Go Away Green”, so while the UFOs are probing Clara, visitors are focused on finding Hidden Mickeys.

Ufo sightings happen all over the world, but since that's a fringe science at best or outright scam at worst, you don't find any references in international mass media.

Once you search domestically in the respective language of a country, you'll get your share of results.

For example:

https://www.dw.com/en/ufos-and-aliens-in-germany/a-58077707

However at least of the German UFO clubs seem to be perfectly reasonable:

In Germany, there seems to be an endless list of hobby clubs and nonprofit associations. The Association for UFO Research (GEP) is one of them. Their databank includes 140,000 entries, and 95% of them can be explained. Aside from satellites, strangely shaped balloons is one common answer, as well as weather phenomena and insects that zoom across photos. The remaining 5% "perhaps also have natural causes, which we just can't explain yet," Hans-Werner Peiniger, GEP's head, told DW. Members of Germany's UFO clubs — there are at least three — are not blind alien believers, Leipzig-based Fleischer said. They are rational, engineer types who use limited resources to analyze what curious sky watchers send them. The result, however, can be a great deal of information about what is happening above us. The really interesting cases "are a matter for the military," Fleischer said. "They control the skies and have instruments and radar."
- "Of course we have a UFO sighting club. It keeps detailed and well-organised records and 95% of sightings have perfectly ordinary explanations."
  
  That's some peak Germany right there. Amazing.

The perfectly marbled fat on American thighs gives you all such an exquisite flavour.

More interesting question is how the hell in a world with 4k phone cameras we still only get blurry vhs tape quality videos.

Exactly.
Cause they're fake.
- Take your rock.
This premise is also false. Go on youtube to see high definition video of UFOs.

There are tons of sightings, and yes they went up with the advent of phones.

They aren't strictly, speaking.

The UFO craze kicked off just after WW2 in the US, so you initially had a lot there.

https://en.wikipedia.org/wiki/Unidentified_flying_object

While unusual sightings have been reported in the sky throughout history, UFOs became culturally prominent after World War II, escalating during the Space Age.

In the Pacific and European theatres during World War II, round, glowing fireballs known as "foo fighters" were reported by Allied and Axis pilots. Some explanations for these sightings included St. Elmo's fire, the planet Venus, hallucinations from oxygen deprivation, and German secret weapons (specifically rockets).[15] In 1946, more than 2,000 reports were collected, primarily by the Swedish military, of unidentified aerial objects over the Scandinavian nations, along with isolated reports from France, Portugal, Spain, Italy, and Greece. The objects were referred to as "Russian hail" (and later as "ghost rockets") because it was thought the mysterious objects were possibly Russian tests of captured German V1 or V2 rockets, but most were identified as natural phenomena as meteors.[16]

Many scholars, especially those arguing for the psychosocial UFO hypothesis, have noted that UFO characteristics reported after the first widely publicized modern sighting by Kenneth Arnold in 1947 resembled a host of science fiction tropes from earlier in the century.[17][18][19][20][21][22][23]

https://en.wikipedia.org/wiki/1947_flying_disc_craze

The 1947 flying disc craze was a rash of unidentified flying object reports in the United States that were publicized during the summer of 1947. The craze began on June 24, when media nationwide reported civilian pilot Kenneth Arnold's story of witnessing disc-shaped objects which headline writers dubbed "Flying Saucers". Such reports quickly spread throughout the United States; historians would later chronicle at least 800 "copycat" reports in subsequent weeks, while other sources estimate the reports may have numbered in the thousands.