As far as I know only one top level player and referee have come out - Gareth Thomas and Nigel Owens - both Welsh as it happens but maybe that’s coincidence. My wife occasionally makes a comment on the lines of possible homosexual tendencies when I have the rugby on and they’re really knocking hell out of each other. Not my idea of a sexual good time.Rugby and boxing have far more physical contact, since they're less popular than football I imagine it's a bit easier to "come out" in those sports.
As for openly gay footballers, Thomas Hitzlsperger revealed his homosexuality after his retirement. Justin Fashanu came out during his playing career in the 90s (when homosexuality was far more taboo than today).