I was born here but my entire family is Jamaican and i have been to visit family almost every year of my life and i can tell you at least any Jamaican generation i have had experience with feels the same way as the people you know OP.
From my experience and what i know of Jamaica and its people is that they view themselves as a bit of an underdog with a wealth of wonders to show the world. Its a fiery vibrant warm and kind culture of people. Hard working country folks. Resilient and uniquely ingenious. Living in gully side zinc shacks and opening diesel rig mechanic shops or shrimp boil stalls to make ends meet and fill a need. You can feel the spirit of the taino arowak and redware natives. You can feel the spirit of the maroons who still have an autonomous settlement and government in the heavily wooded areas in the center of the island. A place with unique history and it's own version of Atlantis mythology that actually happened (Port Royal). Im not sure if this is true but it is said that the more rebellious people were dropped off in Jamaica first during the slave trade.
All of these things contribute to a unique culture. One that is intensely strong and proud and inviting to the world. I could go on about examples of my family members interactions with people outside of Jamaican culture but it colors every aspect of life when abroad whether living or visiting.
Im sure there is a growing group of the Jamaican gen z that is "waking up" but based on my loose connection to them through Jamaican entertainment podcasters that is still a very small group. Those people and devout rastas probably hate white surfers with dreads and the movie cool runnings. But my cousins and my uncle and my mom really like the mighty quinn with Denzel even though his accent wasnt that great. The fact that we got a shout out from the big media machine was a moment of celebration. You all saw how proud and loud the entire island was in supporting Usain Bolt, or at least i did first hand.
Honestly it is pretty incredible when you think about how much influence such a small island with less than 3 million population has on the world in culture and media. There are Sound system and dancehall queen competitions in almost every major city in the world and you can hear reggae basslines and vocal samples in every genre of music in most countries in the world.
All that context to say, a perfect example of the OP post is when people were mad at skinny adele for the braids and the Jamaican flag bra. "Thats not your culture!" But it is though. Because Adele grew up around a British town with a strong influence from Jamaican immigrants. She ate the food listened to the music had friends and went to the Nottingham carnival celebration. I think thats the one im not sure. So she was expressing her culture. Jamaicans all over the world were just thrilled that Adele was showing love to the Land of wood and water. The Jamaicans in England knew she was representing with respect to the diaspora and defended her from the white people in America that either have no idea that people in some parts of the world can coexist and share in celebration of cultures or hate that it happens. And yes I am aware that the main goal by those that have logical sense is that they want representation amd credit and authenticity, which is great. Just don't be so quick to assume, get offended, and fly to defense of people that may not be asking or needing the defense. Then it starts to look like you just want the world to know youre one of the good ones.
I mean the entire slang vocabulary of English in England at least in the south is based on Jamaican English and patois. Similar to Toronto which also has a huge presence of Caribbean people.
TL
R just know that Jamaicans wont cancel you if you like reggae or wear a rasta beanie for Halloween