You can't compare it to the Christian society - Christianity has longstanding power in our society, not a history of being oppressed.
Unless I missed the recent history where vast swathes of our society strongly believed homosexuality was immoral and that it was acceptable - nay, advisable - to ostracise anybody who dared to live their lives as a gay person. Not to mention informing them that they deserved to, and would, burn in hell. Who seemed to revel in telling them that AIDS was their punishment from God for being gay.
Did I miss that happening to Christians very recently, and on a smaller scale continuing today?
Did I miss Christians being imprisoned in living memory? Having their entires lives ruined by criminal convictions for simply living as themselves?
No. Didn't think so.
Not the same.
Homophobia is not a legitimate or defensible "view". It's prejudice and discrimination.
A Christian cross is a statement of faith, a rainbow lanyard is a statement of not being homophobic. That you accept your colleagues without judgement.
Being straight is not a lifestyle choice, and nor is being gay. "I don't care who people are seeing" is bollocks when it comes from straight people who've never had to think twice about whether it's safe for them to mention their own partner's name in passing, let alone talk about them or the life they share. Who've never had colleagues whispering about their sexuality, or attributing every nuance of their personality to their sexuality.
Or do you keep being straight a secret from your colleagues, never making any reference to any part of your life that might give you away, such that they could accuse you of sharing "unnecessary" personal details?
Or do you feel safe to unthinkingly make casual references to it whenever you fancy, without any fear of backlash, judgement, or rejection, because you're safe in the knowledge you're "normal" and everybody has already assumed you to be that way and accepted you as you are?
Have you even stopped to consider this from the other side?