Speaking of Bedouins, our forefather Avrohom Yitzchok and Yaakov, being shepherds in Eretz Yisroel, its hills and deserts, would have likely, almost certainly, worn clothing not dissimilar to a modern Bedouin. Not a shtreimel, bekeshe, hat, double layered yarmulke, gartel or black suit to be seen. Which, of course, begs the question. Did our forefathers daven dressed as prescribed here, by Rav Kanievsky, or anyone else? Did it impact on their tefilos? What about (hypothetical) Eliezer from Shilo who herded Goats during the time of Shmuel Hanovi and brought korbanos to the Mishkan when appropriate. A gartel? A Borsalino?
Was his offering Pigul without it?
Let me be clear. If an individual or the Posek he follows insists it is necessary FOR HIM, boruch Hashem. Wear a hat. Do it with the knowledge that you are upholding Halocho in the manner you and your Rov feel is best.
But unless you want to condemn those who you have no right condemning for doing it differently, Please be less insistent about the practice of others when they are davening and talking to their God.