It's not the "Palestinian national symbol".
"The keffiyeh or kufiyyeh (Arabic: كُوفِيَّة, romanized: kūfiyya, lit. 'coif'),[1] also known in Arabic as a hattah (حَطَّة, ḥaṭṭa), is a traditional headdress worn by men from parts of the Middle East. It is fashioned from a square scarf, and is usually made of cotton.[2] The keffiyeh is commonly found in arid regions, as it provides protection from sunburn, dust, and sand. The regional variations are called ghutrah and shemagh. A head cord, agal, is often used by Arabs to keep the ghutrah in place.[3]".
I never said it was religious, but it is associated with Islamic celebrations because Islam and Middle Eastern culture are closely intertwined. People are wearing them more frequently currently because it's Ramadan, in the same way that I wear a Christmas jumper pretty much every day in December. Which is also not a religious item, but when I wear it, people know it's because I'm celebrating Christmas - not once has anyone assumed it's because I'm making a "political statement" (not sure what that would be about - maybe Western nationalism or something).
The only reason people are assuming it's something sinister is because it's Muslims wearing it. There's absolutely no way you or the OP would be starting and AIBU on December complaining that Craig from Asda was wearing a Santa hat at work.