"I really want to do the thing! All of my friends who are just like me are doing the thing, and they look like they're having so much fun!"
"You can totally do the thing! You just have to sign ... this loyalty oath!"
(reading it) "What? I can't sign this. It's, it's—" (rising horror) "not scientifically accurate!"
"Everyone else who is doing the thing has signed the loyalty oath."
"Could I ... do the thing, without signing the loyalty oath?"
"You could, but everyone you ever interact with for the rest of your life will assume that you've signed the loyalty oath; it would take five hours for you to explain what you actually believe, but no one will listen to you for that long because they'll decide that you're a hateful lunatic thirty seconds in."
(A beat.)
"You know, honestly, my life is fine as it is. I don't need to do the thing. I'm glad my friends are having fun."
(dies of cardiac disease fifty years later without having done the thing)
(Earth is consumed in a self-replicating nanotechnology accident)
Write it in very small print on your shirt and that way people can read your manifesto concurrently with other activities.
"Have my friends who are doing the thing signed the loyalty oath?"
"Well...no... We mostly didn't tell them about it actually."
"But surely they know about it, if they're doing the thing!"
"Oh sure. Every so often while they're doing the thing, someone asks if they're following the loyalty oath. They say yes, of course."
"But, then... why couldn't I just do the thing without this whole conversation?Why tell ME?"
"Well, you're a very honest man, and that sort of virtue deserves to be reciprocated."