1. It’s absolutely possible that they hold it’s assur, but “k’sheim shmitzvah lomar davar hanishma…etc”. I don’t think I ever saw a psak saying it’s “muttar”.
Sure there is, in America they have specifically allowed use of smartphones with filters. V’Harayah, the head of the Agudah in America uses one (and famously had it go off in the middle of his speech during a convention).
2 But I don’t actually think that’s the case. I think that Halachically all the Gedolim agree that having unfiltered internet is absolutely assur, whether it’s on a smartphone or a PC. Gedolim in E”Y, however, realizing that the vast majority of those with smartphones don’t actually get a filter for it, decided that the issue was important enough to go and make a geder. The Gedolim in the US, however, realize the American tzibur wouldn’t adhere to a geder like that.
So you admit that it is a geder made up by the gedolim in Eretz Yisroel, vs. an actual psak/Issur. End story, may someone own a smartphone with a filter al pi Halacha? The answer to that is yes. However, in EY the Gedolim said it was Assur none the less because…the Tzibbur there is more pliable to societal pressure? Because the Tzibbur is unable to make distrinctions between filtered and unfiltered internet? Or perhaps because the Tzibbur does not need to be connected as Charaidim shouldn’t be working anyway?
Besides, you didn’t answer my main point. If you believed that there should have been a Geder created in America, but there wasn’t for external reasons, why did you own a smartphone in America? What changed?