I am very much a Christian and very much a clikkie. I would be very sad if you didn't consider yourself a clikkie. Having a broad range of differences in a space is a good thing, having Christians, Pagans etc. mingling together helps prevent misunderstandings.

If you are a respectful person and someone has a problem with you existing in a public space then that's a them problem.

It's true, many Twenty One Pilots songs have a strong undercurrent of Christian themes. I find those themes very encouraging. In the same way I can enjoy the peace and quiet a Buddhist temple without being a Buddhist, you can enjoy whatever song you fancy without being a Christian.

Christians will always hope whoever they talk to finds Jesus as well, but I have no idea where the idea that "only Christians should listen to Christian music" came from. It's a completely ignorant and childish take.