As a gay fan, it depresses me seeing some of the reactions to this campaign. Those who think there is no issue with homophobia (and racism for that matter) in football have their heads buried in the sand. I wouldn't say this is a regular thing, but I've heard homophobic comments shouted at both home and away players several times a season since I can remember - only on Tuesday did a fella next to me shout at Bernardo Silva to "not be such a poofter" when he went down easily and then looked at the referee for sympathy. Last season, I started challenging the fans in question if I knew where it came from or reporting incidents to the club if not - one shouted at Sterling because of the way he runs, one shouted at the referee for not giving a free kick (which was, at best, a dubious decision anyway), and one at an opponent who stayed down and needed treatment.
It's funny that I've also heard the odd racist comment from the stands and they've been challenged by four or five others almost immediately. Nothing is said to those making homophobic comments.
For me, for rainbow laces to work, I think they need to be compulsory - with the players given the option to opt out. That way, if they don't want to take part, they have to actively make the choice to, rather than being able to hide behind not knowing about the campaign or forgetting or whatever. If they want to give a reason, they can. If they don't, they don't have to.
Football is exactly the place to challenge attitudes because football continues to prove itself in need of having those attitudes challenged.