I dunno, I’m Mexican and studied in the USA for a while, during Halloween a bunch of my friends dressed up in Sombreros, Ponchos, fake mustaches and had Tequila for everyone and I thought it was fine.
Hell, I joined in! I wouldn’t say they were being disrespectful to me, or my country or my culture. Most people can tell when something is done in good fun or is just plain disrespectful or racist, say I decided to dress up as an american cowboy, or a sheriff or Uncle Sam or any other depiction of american culture for Halloween. Would I have been culturally appropriating?
Then again that’s me, I can see why some people would be offended but if an app has an option to put a sombrero sticker on a selfie I see no problem at all.