In one of my two native tongues there's an expression which, if literally translated, would sound somewhat like: "to make it one's flag"...
It may be used in a positive sense, connoting that someone has really devoted himself/herself to exercising his/her ideals in practice - and chances are that this is the prevalent usage - but it can also be amenable to a pinch of irony when such devotion is shown towards things that are commonly admitted as repercussions of vanity, or perhaps even sheer foolishness.
Here's a few examples where it might be used in the latter sense:
Getting together with your pals for a poker evening every once in a while is one thing.
Makinggamble your flagis quite another.
I can understand he finds it difficult to cut smoking; but that doesn't mean I approve of him strolling around,
making“anti-hygienism” - or whatever you wanna call it - his flag!
I wonder if there is some English half-slangy (non-offensive) idiom that might do the same trick?
(Hope this one's clear enough).